Brain-specific drug delivery of steroid sex hormones cleaved from pyridinium carboxylates and dihydro-pyridine carboxylate precursors

ABSTRACT

The subject compounds, which are adapted for the site-specific/sustained delivery of centrally acting drug species to the brain, are: 
     (a) compounds of the formula 
     
         [D--DHC]                                                   (I) 
    
      wherein [D] is a centrally acting drug species, and [DHC] is the reduced, biooxidizable, blood-brain barrier penetrating lipoidal form of a dihydropyridine⃡pyridinium salt redox carrier, with the proviso that when [DHC] is ##STR1##  wherein R is lower alkyl or benzyl and [D] is a drug species containing a single NH 2  or OH functional group, the single OH group when present being a primary or secondary OH group, said drug species being linked directly through said NH 2  or OH function group to the carbonyl function of [DHC], then [D] must be other than a sympathetic stimulant, steroid sex hormone or long chain alkanol; and 
     (b) non-toxic pharmaceutically acceptable salts of compounds of formula (I) wherein [D] is a centrally acting drug species and [DHC] is the reduced, biooxidizable, blood-brain barrier penetrating lipoidal form of a dihydropyridine⃡pyridinium salt redox carrier. The corresponding ionic pyridinium salt type drug/carrier entitles [D--QC] +  X -   are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my earlier copendingapplications Ser. No. 379,316, filed May 18, 1982, now U.S. Pat. No.4,449,932, filed Jan. 27, 1983, abandoned in favor of Ser. No. 733,463,filed May 13, 1985; Ser. No. 475,493, filed Mar. 15, 1983, now U.S. Pat.No. 4,622,218 and Ser. No. 516,382, filed July 22, 1983, now U.S. Pat.No. 4,540,564. Each of said earlier copending applications is herebyexpressly incorporated by reference herein in its entirety and reliedupon.

FIELD OF THE INVENTION

The present invention relates to a dihydropyridine/pyridinium salt typeor redox system for the site-specific or sustained delivery (or both) ofa wide variety of drug species to the the brain. More especially, thisinvention relates to the discovery that a biologically active compoundcoupled to a lipoidal carrier moiety comprising a dihydropyridinenucleus readily and easily penetrates the blood-brain barrier ("BBB")and attains increased levels of concentration in the brain; oxidation ofthe dihydropyridine carrier moiety in vivo to the ionic pyridinium saltsprevents its elimination from the brain, while elimination from thegeneral circulation is accelerated, resulting in significant andprolongedly sustained brain-specific drug activity, whether ascribableto the cleavage of the [D--QC]⁺ entity and sustained release of the drugin the brain and/or to [D--QC]⁺ itself.

BACKGROUND OF THE INVENTION

The delivery of drug species to the brain is ofttimes seriously limitedby transport and metabolism factors and, more specifically, by thefunctional barrier of the endothelial brain capillary wall deemed theblood-brain barrier, BBB. Site-specific delivery and sustained deliveryof drugs to the brain are even more difficult, and to date (i.e. priorto the dates of applicant's earlier copending applications) no usefulsimple or generic techniques to achieve such phenomena are known to theart.

Indeed, the barriers separating plasma from the brain and cerebrospinalfluid (CSF) are complex systems involving passive and active transportand subserve a number of important functions. The boundary betweenplasma and the central nervous system (CNS) is much less permeable thanthat between plasma and other tissue cells to a variety of water solublesubstances, such as organic electrolytes, organic acids and bases, aswell as to large molecules such as proteins. Such a barrier alsoprovides a path for clearance from the brain of the breakdown productsof cellular metabolism. The CNS and its fluids can be consideredbasically a three-compartment system: the blood or the plasma, CSF andbrain tissue. There is a diffusion-controlled exchange between CSF andthe extracellular fluid (CF) of the brain. It has also been suggestedthat the permeabilities of blood-CSF and blood-brain barriers arepractically identical with respect to drugs and other foreignsubstances. Mayer et al, J. Pharmacol. and Exp. Therap., 125, 185(1959).

The BBB is, moreover, basically the result of the fact that theendothelial cells in the brain capillaries are joined by continuous,tight intercellular junctions, such that material has to pass throughthe cells rather than between them in order to move from blood to brain.It is interesting that there are areas within the brain, such as thesubfornical body and the postremia, in which the capillary cells are notclosely linked so that they lack the characteristics of the BBB. Theyprovide the entry of small amounts of compounds which would notordinarily enter the barriers. Hoffman and Olszewzki, Neurology(Minneap.), 11, 1081 (1961).

Foreign compounds which enter organs other than the central nervoussystem with ease, may penetrate the CNS slowly or hardly at all. Anumber of theories concerning the nature of the barrier have beenproposed. The widely accepted concept describes the boundary as afat-like layer interspersed with small pores, although the BBB is not asimple, anatomically well-defined unitary physical entity. Shuttleworth,Prog. Exp. Tumor Res., 17, 279 (1972). Penetration of such a barrier mayoccur by several processes: lipid soluble substances may passivelypenetrate into the cells, while small molecules such as water and ureamay pass through the pores. In addition to these simple physicalprocesses, carrier-mediated and active transport processes govern themovement of many molecules through the BBB. Thus, it is generallyaccepted that lipid solubility, degree of ionic dissociation orprotonation and the ability of temporary combination with membraneconstituents affect delivery through the BBB. It has been shown, forexample, that in the class of barbiturates, a quantitative correlationcould be established between their ease to pass into the brain (asreflected by the different times of onset of anesthetic action) andtheir lipid/water partition coefficient. Mark et al, J. Pharmacol. andExp. Therap., 123, 79 (1957). The role of lipid solubility in drugpenetration through the BBB is also exemplified by the better absorptionof the sparingly water-soluble thiamine propyl disulfide (TPD) ascompared to the water-soluble thiamine hydrochloride (THCl). Thomson etal, Ann. Int. Med., 74,Z 529 (1971). Some materials such as glucose andamino acids are transported by active mechanism, characterized bysaturation, bidirectional molecular specificity, bidirectionalcompetitive inhibition and bidirectional countertransport. Fishman, Am.J. Physiol., 206, 836 (1964).

Changes in permeability of the BBB can be caused by several pathologicaland toxicological processes. Pardridge, Connor and Crawford, CRC Crit.Rev. Toxicol., 179 (1975). A general increase in the barrierpermeability, such as a nonspecific breakdown of the barrier has,however, severe consequences, including cerebral edema.

It too is well documented that the BBB is relatively impermeable to theionized forms of drugs and other molecules. Drugs which are weak organicelectrolytes appear to pass from blood to CSF to reach a steady stateratio characteristic of each molecule according to its pK_(a) and theexistence of a normal pH gradient between blood and CSF. It is clearthat it is the most difficult for quaternary pyridinium or ammonium saltto penetrate the BBB.

And removal of substances from the brain and CSF is obviously asignificant factor in regulating drug concentrations in the CNS. Thereare several efflux processes: bulk flow via the arachnoid villi,diffusion of lipid soluble substances into brain and blood, activetransport and metabolism by adjacent meninges. Once a drug or metaboliteenters the CSF from blood or brain by simple diffusion, it may rapidlybe removed, either by nonselective bulk flow or by active transportmechanism associated with the choroid plexus or other nondefinedstructures in the CSF compartment. It is generally accepted that highlylipid-soluble drugs leave the CSF more rapidly than poorly lipid-solubleones, but the barrier to passage of compounds from CSF has onlysuperficial similarity to the blood-CSF barrier.

Drug elimination processes from the brain are significantly directlyrelated to drug accumulation in the brain. It is generally assumed thatefflux in the opposite direction involves almost the same processes asfor entry, except that the role of the bulk flow and the metabolicprocesses in the brain are not to be overlooked.

The two elimination processes studied in the earlier literature andwhich can be said to have a certain bearing on the present inventioninvolve elimination from the brain of ionic species. Thus, it is foundthat non-metabolized ionic species, such as the acetate ion, have athree times slower elimination rate from the CSF than from the blood.Freundt, Arz., Forsch., 23, 949 (1973). An even more dramatic change inthe elimination rate was found in the case of a quaternary piperidiniumsalt. The quaternary salt, formed in situ after delivery of ahaloalkylamine, which undergoes cyclization to the quaternary salt, inthe brain, as well, was found to have an at least ten times slowerelimination rate from the brain than from the rest of the body. It wasconcluded by the authors [Ross and Froden, Eur. J. Pharmacol., 13, 46(1970)] that the outflow rate of the quaternary salt corresponded to theinflow rate. Similar results were obtained for the erythrocytes: theefflux of the quaternary salt was very slow. Ross, J. Pharm. Pharmacol.,27, 322(1975).

And while it too has been suggested to deliver a drug species,specifically N-methylpyridinium-2-carbaldoxime chloride (2-PAM), intothe brain, the active nucleus of which in and of itself constitutes aquaternary pyridinium salt, by way of the dihydropyridine latentiatedprodrug form thereof, such approach was conspicuously delimited torelatively small molecule quaternary pyridinium ring-containing drugspecies and did not provide the overall ideal result of brain-specific,sustained release of the desired drug, with concomitant rapidelimination from the general circulation, enhanced drug efficacy anddecreased toxicity. Hence, no "trapping" in the brain of the 2-PAMformed in situ resulted, and obviously no brain-specific, sustaineddelivery occurred as any consequence thereof: the 2-PAM was eliminatedas fast from the brain as it was from the general circulation and otherorgans. Compare U.S. Pat. Nos. 3,929,813 and 3,962,447; Bodor et al, J.Pharm. Sci., 67, No. 5, pp. 685-687 (1978); Bodor et al, Science, Vol.190 (1975), pp. 155-156; Shek, Higuchi and Bodor, J. Med. Chem., Vol. 19(1976), pp. 113-117. A more recent extension of this approach isdescribed by Brewster, Dissertation Abstracts International, Vol. 43,No. 09, March 1983, p. 2910B. It has also been speculated to deliver,e.g., an antitumor agent, into the brain by utilizing adihydropyridine/pyridinium redox carrier moiety therefor, but thisparticular hypothesis necessarily entails derivatizing thedihydropyridine/pyridinium carrier with a substituent itself criticallydesigned to control the release rate of the active drug species from thequaternary derivative thereof, as well as being critically functionallycoordinated with the particular chemical and therapeutic activity/natureof the anti-tumor drug species itself; Bodor et al, J. Pharm. Sci.,supra. See also Bodor, "Novel Approaches for the Design of MembraneTransport Properties of Drugs", in Design of BiopharmaceuticalProperties Through Prodrugs and Analogs, Roche, E. B. (ed.), APhAAcademy of Pharmaceutical Sciences, Washington, D.C., pp. 98-135 (1976).Moreover, the hypothesis does not include any indication of whatchemical transformations would be needed to link any specific antitumoragent (or indeed any specific drug) to an appropriate carrier moiety.

Accordingly, acutely serious need exists in this art for a trulyeffective generaic but nonetheless flexible method for thesite-specific, or sustained delivery, or both, of drug species to thebrain, while at the same time avoiding the aforesaid noted and notabledisadvantages and drawbacks associated with penetration of theblood-brain barrier, with dihydropyridine latentiated prodrug forms ofdrug species themselves comprising a pyridinium salt active nucleus, andwith the necessity for introducing critically coordinated and designed,release rate-controlling substituents onto any particular drug carriermoiety. This need has been addressed by applicant's earlier copendingapplications referred to hereinabove, and especially by the Serial Nos.379,316 and 516,382, and is also addressed by the present application.

It is also known to this art that Parkinsonism, a striatal dopaminedeficiency syndrome [H. Ehringer and O. Hornykiewicz, Klin. Wsch., 38,1236 (1960)], cannot be treated directly with dopamine, for dopamine andrelated catecholamines also do not cross the blood-brain barrier ([B. E.Roos and G. Steg, Life Sci., 3, 351 (1964)]. L-Dopa, considered as aprodrug for dopamine, was first discovered to be useful in the treatmentof Parkinsonism more than twenty years ago [A. Barbeau, Excepta Medica,Int. Congr. Ser., 38, 152 (1961); W. Birkmayer and O. Hornykiewicz,Wien. Klin. Wochnenschr., 73, 787 (1961)]. Indeed, L-Dopa is consideredto be the best available treatment for Parkinsonism, but, unfortunately,at the expense of a wide variety of undesirable side effects [A.Barbeau, TIPS, 2, (11), 297 (1981]. The peripheral side effects ofL-Dopa, which range from nausea and vomiting to cardiac arrythmias andhypotension, appear to be due to one or more of the metabolic productsthereof, rather than L-Dopa per se. L-Aromatic amino acid decarboxylaseenzyme is responsible for the major metabolism of L-Dopa, whether prior,during or after absorption. Concurrent administration of L-Dopa with aninhibitor of aromatic amino acid decarboxylase, which should not be ableto penetrate the BBB, reduces the decarboxylation of L-Dopa inperipheral tissues. Such reduction allows higher proportions of L-Dopato reach the CNS and at the same time diminishes the peripheral sideeffects considerably, particularly vomiting and cardiac arrythmias, buta number of serious side effects still persist [A. Barbeau, TIPS, supra;A. Barbeau ad M. Roy, Neurology, 26, 399 [(1976)]. Attempts have alsobeen made to alleviate the well-known dissolution, absorption andmetabolism problems of L-Dopa [H. Ninterberger, Biochem. Med., 5, 412(1971); H. Shindo, T. Komai, K. Tanaka, E. Nakajima and N. Miyakoshi,Chem. Pharm. Bull., 21, 826 (1973); C. O. Rutledge and M. M. Hoehn,Nature (London), 244, 447 (1973); R. L. Bronaugh, R. J. McMurty, M. M.Hoehn and C. O. Rutledge, Biochem. Pharmacol., 24, 1317 (1975)],employing prodrug approaches [N. Bodor, K. B. Sloan, T. Higuchi and K.Sasahara, J. Med. Chem., 20, 1435 (1977); A. M. Felix, D. P. Winter, S.S. Wang, I. D. Kulesha, W. R. Pool, D. L. Hane and H. Sheppard, J. Med.Chem., 17, 422 (1974)].

Additional, dopamine agonists, which are used in the treatment ofhyperproclactinemia associated with pituitary adenomas or amenorrhea [R.F. Spark and G. Dickenstein, Ann. Int. Med., 90, 949 (1979)], alsoinduce unwanted side effects.

Thus, especially acutely serious need exists in this art to deliver adopaminergic agent directly and specifically to the brain, in asustained manner, and there elicit the desired dopaminergic response,e.g., for the treatment of the Parkinsonism or hyperprolactinemia. Thisneed has been addressed by applicant's earlier copending applicationsreferred to above, and especially by the Ser. No. 461,543, and is alsoaddressed by the present application.

SUMMARY AND OBJECTS OF THE INVENTION

Accordingly, a major object of the present invention is the provision ofa generic method for the specific and/or target enhanced delivery to thebrain of a wide variety of drug species and to achieve brain-specificdrug delivery by effecting the bidirectional transport of the drugspecies into and out of the brain employing dihydropyridine⃡pyridiniumsalt carrier type redpox systems.

Another object of the invention is to provide for brain specific drugdelivery utilizing a dihydropyridine⃡pyridinium salt carrier type redoxsystem, shich drug/carrier system is characterized by enhanced drugefficacy and decreased toxicity. Indeed, consistent herewith systemictoxicity is significantly reduced by accelerating the elimination of thedrug/quaternary carrier system, and even central toxicity is reduced byproviding a low level, sustained release of the active drug species inthe brain.

Yet another object of this invention is the provision of a chemicaldelivery system for the site-specific and sustained release of drugspecies to the brain, and one in which a special pro-prodrug reducedform of an active drug species is actually delivered to the body of apatient, not a prodrug as such and not a drug/carrier entity necessarilycomprised of critically tailored release rate-controllingsubstituent(s).

Yet another object of this invention is to provide enhanced delivery tothe brain of a wide variety of centrally acting agents which are notthemselves able to penetrate the blood-brain barrier to any considerableextent.

Briefly, the present invention features a dihydropyridine⃡pyridinium saltcarrier redox system for the specific and sustained delivery of drugspecies to the brain according to the following Scheme 1: ##STR2##Consistent with the foregoing Scheme 1, any drug species [D] is coupledto a quaternary pyridinium salt carrier [QC]⁺ and the prodrug ([D--QC⁺which results is then reduced chemically to the lipoidal dihydropro-prodrug form [D--DHC]. Alternatively, the drug species [D] can bedirectly coupled to the dihydro carrier [DHC] in certain instances toyield said pro-prodrug form [D--DHC]. After administration of the[D--DHC] in vivo, it is rapidly distributed throughout the body,including the brain . The dihydro form [D--DHC] is then in situ oxidized(rate constant, k₁) (by the NAD⃡NADH system) to the ideally inactiveoriginal [D--QC]⁺ quaternary salt prodrug, which, because of its ionic,hydrophilic character, is rapidly eliminated from the generalcirculation of the body, while the blood-brain barrier prevents itselimination from the brain (k₃ >>k₂ ; k₃ >>k₇). Enzymatic cleavage ofthe [D--QC] that is "locked" in the brain effects a sustained deliveryof the drug species [D], followed by its normal elimination (k₅),metabolism. A properly selected carrier [QC]⁺ will also be rapidlyeliminated from the brain (k₆ >>k₂). Because of the facile eliminationof [D--QC⁺ from the general circualtion, only minor amounts of drug arereleased in the body (k₃ >>k₄); [D] is released primarily in the brain(k₄ >k₂). The overall result is a brain-specific, sustained release ofthe target drug species. Cf. Bodor et al, Science, Vol. 214, Dec. 18,1981, pp. 1370-1372; The Friday Evening Post, Aug. 14, 1981, HealthCenter Communications, University of Florida, Gainesville, Fla; Chemical& Engineering News, Dec. 21, 1981, pp. 24-25; Science News, Jan. 2,1982, Vol. 121, No. 1, page 7. See also Bodor et al, J. Med. Chem., Vol.26, March 1983, pp. 313-317; Bodor et al, J. Med. Chem., Vol. 26, April1983, pp. 528-534; Bodor et al, Pharmacology and Therapeutics, Vol. 19,No. 3, pp. 337-386 (April 1983); Bodor et al, Science, Vol. 221, July1983, pp. 65-67; and Bodor et al, J. Pharm. Sci., Vol. 73, No. 3, March1984, pp. 385-388.

In accord with the foregoing, the present invention provides compoundsadapted for the site-specific/sustained delivery of a centrally actingdrug species to the brain, said compounds being:

(a) compounds of the formula

    [D--DHC]                                                   (I)

wherein [D] is centrally acting drug species, and [DHC] is the reduced,biooxidizable, blood-brain barrier penetrating lipoidal form of adihydropyridine⃡pyridinium salt redox carrier, with the proviso that when[DHC] is ##STR3## wherein R is lower alkyl or benzyl and [D] is a drugspecies containing a single NH₂ or OH functional group, the single OHgroup when present being a primary or secondary OH group, said drugspecies being linked directly through said NH₂ or OH functional group tothe carbonyl function of [DHC], then [D] must be other than asympathetic stimulant, steroid sex hormone or long chain alkanol; or

(b) non-toxic pharmaceutically acceptable salts of compounds of formula(I) wherein [D] is a centrally acting drug species and [DHC] is thereduced, biooxidizable, blood-brain barrier penetrating lipoidal form ofa dihydropyridine⃡pyridinium salt redox carrier.

In another aspect, the present invention provides compounds having theformula

    [D--QC].sup.+ X.sup.-                                      (II)

wherein X⁻ is the anion of a non-toxic pharmaceutically acceptable acid,[D] is a centrally acting drug species and [QC]⁺ is the hydrophilic,ionic pyridinium salt form of a dihydropyridine⃡pyridinium salt redoxcarrier, with the proviso that when [QC]⁺ is ##STR4## wherein R is loweralkyl or benzyl and [D] is a drug species containing a single NH₂ or OHfunctional group, the single OH group when present being a primary orsecondary OH group, said drug species being linked directly through saidNH₂ or OH functional group to the carbonyl function of [QC]⁺, then [D]must be other than a sympathetic stimulant, steroid sex hormone or longchain alkanol.

The present invention further provides a generic method for specificand/or target enhanced delivery to the brain of a wide variety ofcentrally acting drug species, such brain-specific drug delivery beingeffected via the bidirectional transport of the drug species into andout of the brain by means of dihydropyridine⃡pyridinium salt carrier typeredox systems.

In yet another aspect, the present invention provides, as an effectivedopaminergic chemical delivery system, compounds having the formula

    [D--DHC]                                                   (I)

and non-toxic pharmaceutically acceptable salts thereof, wherein [D] isa dopamine having the structural formula ##STR5## in which each Y isindependently hydrogen or a hydrolytically or metabolically cleavablehydroxyl protective group, and [DHC] is the reduced, biooxidizable,blood-brain barrier penetrating, lipoidal form of adihydropyridine⃡pyridinium salt redox carrier.

In still another aspect, the present invention provides compounds havingthe formula

    [D--QC].sup.+ X.sup.-                                      (II)

wherein X⁻ is defined above and [D] is a dopamine having the structuralformula ##STR6## in which each Y is independently hydrogen or ahydrolytically or metabolically cleavable hydroxy protective group, and[QC]⁺ is the hydrophilic, ionic pyridinium salt form of adihydropyridine⃡pyridinium salt redox carrier.

Briefly, one presently preferred chemical delivery system for dopamineaccording to this invention has the structure (2) in the followingScheme 2, wherein the amino function of dopamine is appropriately linkedto the dihydropyridine-type carrier system, while the catechol functionis advantageously protected, for example, as a corresponding esterfunction, e.g., the dipivalyl ester illustrated. The brain-specificdelivery of dopamine, or the otherwise eliciting of a dopaminergicresponse, requires a succession of processes, including oxidation of thedihydropyridine ring to the corresponding pyridinium salt (for example,structure 3), which provides the basis for "locking-in" in the brain themolecule, hydrolysis of the, e.g., pivalyl esters (see structure 4)likely via the 3- and/or 4-monopivalyl esters and, finally, the releaseof dopamine (1) from 4, which can be either a hydrolysis or a reductiveprocess [a possible reductive release of dopamine was very recentlysuggested by a model for a presynaptic terminal, L. L. Miller, A. N. K.Lau and E. K. Miller, J. Am. Chem. Soc., 104, 5242 (1982)]. ##STR7##

As per the above Scheme 2, for the brain specific delivery of dopamine(1), structure 2 is one chemical delivery system consistent herewith,and 4 is one precursor locked in the brain and eliminated rapidly fromthe rest of the body. Structures 3 depict intermediates formed duringthe stepwise hydrolysis and oxidation processes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph plotting the time course of1-methyl-3-{N-[β-(3,4-dipivalyloxphenyl)ethyl]}carbamoyl-1,4-dihydropyridine5c (O) and its products, the monopivalyl-dihydro derivative 11 (∇), thedihydrodopamine derivative 5a ( ) and the quaternary dopamine precursor6c ( ) in plasma;

FIG. 2 is a graph plotting the time course of1-methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine5c (O) and its products, the monopivalyl-dihydro drivative 11 (∇) andthe quaternary dopamine precursor 6a ( ) in whole blood;

FIG. 3 is a graph plotting the time course of1-methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine5c (O) and its products, the monopivalyl-dihydro derivative 11 (∇), thedihydrodopamine derivative 5a ( ) and the quaternary dopamine precursor6a ( ) in 20% brain homogenate;

FIG. 4 is a graph plotting the time course of1-methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]}carbamoyl-1,4-dihydroxypridine5c (O) and its product, the quaternary dopamine precursor 6a ( ) in 20%liver homogenate;

FIG. 5 is a semilog plot of peak heights of1-methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine5c against time in plasma ( ), brain homogenate ( ), whole blood (O) andliver homogenate (□);

FIG. 6 is a graph plotting concentrations against time of1-methyl-3-{N-[β-(3,4-dihydroxyphenyl)ethyl]}carbamoyl pyridinium cation(6a) in brain ( ) and in blood (O) following administration of1-methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)-ethyl]}carbamoyl-1,4-dihydropyridine(5c), with the error bars indicating SEM;

FIG. 7 is a graph plotting the effects of compounds 5c ( ) and 6a ( )administered I.V. at 1 mg/kg dose level, on the serum prolactin levelsin rats; and

FIG. 8 is a graph plotting concentrations with standard errors againsttime for testosterone-17-nicotinate-N-methyl cation, calculated asiodide, in brain (O) and in blood (□) and concentration of releasedtestosterone (ng/g) in brain ( ), all following administration of thecorresponding dihydropyridine compound. Also plotted are concentrationsof testosterone in brain ( ) and blood ( ) following administration oftestosterone, per se.

DETAILED DESCRIPTION OF THE INVENTION

More particularly in accord with the present invention, the followingdefinitions are applicable:

The term "lipoidal" as used herein is intended to designate a carriermoiety which is lipid-soluble or lipophilic.

The expression "hydroxyl protective group" is intended to designate agroup which is inserted in place of the hydrogen atom(s) of an OH groupor groups in order to prevent premature metabolism of said OH group orgroups prior to the compound's reaching the desired site in the body.Typical hydroxyl protective groups contemplated by the present invention(e.g., for Y in the case of the dopamine derivatives) are acyl groupsand carbonates.

When the hydroxyl protective group is acyl (i.e., when it is an organicradical derived from a carboxylic acid by removal of the hydroxylgroup), it preferably represents an acyl radical selected from the groupconsisting of alkanoyl having 2 to 8 carbon atoms; alkenoyl having oneor two double bonds and 3 to 8 carbon atoms; ##STR8## wherein thecycloalkyl portion contains 3 to 7 ring atoms and r is zero, one, two orthree; phenoxyacetyl; pyridinecarbonyl; and ##STR9## wherein r is zero,one, two or three and phenyl is unsubstituted or is substituted by 1 to3 alkyl each having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbonatoms, halo, trifluoromethyl, dialkylamino having 2 to 8 carbon atoms oralkanoylamino having 2 to 6 carbon atoms.

When the acyl group is alkanoyl, there are included both unbranched andbranched alkanoyl, for example, acetyl, propionyl, butyryl, isobutyryl,valeryl, isovaleryl, 2-methylbutanoyl, pivalyl (pivaloyl),3-methylpentanoyl, 3,3-dimethylbutanoyl, 2,2-dimethylpentanoyl and thelike. Pivalyl, isobutyryl and isovaleryl are especially preferred.

When the acyl group is alkenoyl, there are included, for example,crotonyl, 2,5-hexadienoyl and 3,6-octadienoyl.

When the acyl group is ##STR10## there are included cycloalkanecarbonyland cycloalkanealkanoyl groups wherein the cycloalkane portion canoptionally bear 1 or 2 alkyl groups as substituents, e.g.cyclopropanecarbonyl, 1-methylcyclopropanecarbonyl, cyclopropaneacetyl,α-methylcyclopropaneacetyl, 1-methylcyclopropaneacetyl,cyclopropanepropionyl, α-methylcyclopropanepropionyl,2-isobutylcyclopropanepropionyl, cyclobutanecarbonyl,3,3-dimethylcyclobutanecarbonyl, cyclobutaneacetyl,2,2-dimethyl-3-ethylcyclobutaneacetyl, cyclopentanecarbonyl,cyclohexaneacetyl, cyclohexanecarbonyl, cycloheptanecarbonyl andcycloheptanepropionyl. Cyclohexanecarbonyl is especially preferred.

When the acyl group is pyridinecarbonyl, there are included picolinoyl(2-pyridinecarbonyl), nicotinoyl (3-pyridinecarbonyl) and isonicotinoyl(4-pyridinecarbonyl).

When the acyl group is ##STR11## there are included, for example,benzoyl, phenylacetyl, α-phenylpropionyl, β-phenylpropionyl, p-toluyl,m-toluyl, o-toluyl, o-ethylbenzoyl, p-tert-butylbenzoyl,3,4-dimethylbenzoyl, 2-methyl-4-ethylbenzoyl, 2,4,6-trimethylbenzoyl,m-methylphenylacetyl, p-isobutylphenylacetyl,β-(p-ethylphenyl)propionyl, p-anisoyl, m-anisoyl, o-anisoyl,m-isopropoxybenzoyl, p-methoxyphenylacetyl, m-isobutoxyphenylacetyl,m-diethylaminobenzoyl, 3-methoxy-4-ethoxybenzoyl,3,4,5-trimethoxybenzoyl, p-dibutylaminobenzoyl, p-n-butoxybenzoyl,2,4,6-triethoxybenzoyl, 3,4-diethoxyphenylacetyl,β-(3,4,5-trimethoxyphenyl)propionyl, o-iodobenzoyl, m-bromobenzoyl,p-chlorobenzoyl, p-fluorobenzoyl, 2-bromo-4-chlorobenzoyl,2,4,6-trichlorobenzoyl, p-chlorophenylacetyl,α-(m-bromophenyl)propionyl, p-trifluoromethylbenzoyl,2,4-di(trifluoromethyl)benzoyl, m-trifluoromethylphenylacetyl,β-(p-trifluoromethylphenyl)propionyl, 2-methyl-4-methoxybenzoyl,3-chloro-4-ethoxybenzoyl, β-(3-methyl-4-chlorophenyl)propionyl,p-dimethylaminobenzoyl, p-(N-methyl-N-ethylamino)benzoyl,o-acetamidobenzoyl, m-propionamidobenzoyl,3-chloro-4-acetamidophenylacetyl and p-acetamidophenylpropionyl.

When the hydroxyl protective group is a carbonate grouping, it has thestructural formula ##STR12## i.e., it is an organic radical which can beconsidered to be derived from a carbonic acid by removal of the hydroxylgroup from the COOH portion. Y' preferably represents alkyl having 1 to7 carbon atoms; alkenyl having one or two double bonds and 2 to 7 carbonatoms;

    cycloalkyl--C.sub.r H.sub.2r --

wherein the cycloalkyl portion contains 3 to 7 ring atoms and r is zero,one, two or three; phenoxy; 2-, 3- or 4-pyridyl; or

    phenyl--C.sub.r H.sub.2r --

wherein r is zero, one, two or three and phenyl is unsubstituted or issubstituted by 1 to 3 alkyl each having 1 to 4 carbon atoms, alkoxyhaving 1 to 4 carbon atoms, halo, trifluoromethyl, dialkylamino having 2to 8 carbon atoms or alkanoylamino having 2 to 6 carbon atoms. Mostpreferably, Y' is C₁ -C₇ alkyl, particularly ethyl or isopropyl.

Similarly, the expression "carboxyl protective group" is intended todesignate a group which is inserted in place of the hydrogen atom(s) ofa COOH group or groups in order to prevent premature metabolism of saidCOOH group or groups prior to the compound's reaching the desired sitein the body. Typical carboxyl protecting groups are the groupsencompassed by Y' above, especially C₁ -C₇ alkyl, particularly ethyl,isopropyl and t-butyl. While such simple alkyl esters and the like areoften useful, other carboxyl protecting groups may be selected in orderto achieve greater control over the rate of in vivo hydrolysis of theester back to the acid and thus enhance drug delivery. To that end,carboxyl protecting groups such as the following may be used to replacethe hydrogen of the --COOH group: ##STR13## wherein alk is C₁ -C₆straight or branched alkylene and the alkyl radical is straight orbranched and contains 1 to 7 carbon atoms (e.g. ##STR14##

The expression "amino protective group" as used herein is intended todesignate a group which is inserted in place of the hydrogen atom(s) ofan amino group or groups in order to prevent unwanted reaction of theamino function(s) during chemical synthesis. Such protective groups arewell-known in the art and include t-butoxycarbonyl and carbobenzoxy(i.e. benzyloxycarbonyl). Other appropriate amino protective groups willbe apparent to those skilled in the art. Unlike the instant hydroxyl andcarboxyl protective groups described above, which not only preventunwanted chemical reaction but also protect those hydroxyl and carboxylfunctions from premature metabolism in vivo, the amino protective groupsare primarily intended for use during synthesis and are typicallyremoved by well-known procedures at an appropriate stage of thesynthetic pathway after they have achieved their protective function andare no longer needed. Occasionally, however, an amino protectivefunction will be retained in the compound of formula (I) to also protectthe amino group in vivo.

The term "drug" as used herein means any substance intended for use inthe diagnosis, cure, mitigation, treatment or prevention of disease orin the enhancement of desirable physical or mental development andconditions in man or animal.

By "centrally acting" drug species, active agent or compound as utilizedherein, there is of course intended any drug species or the like, asignificant (usually, principal) pharmacological activity of which isCNS and a result of direct action in the brain.

Exemplary such centrally acting drug species are the CNS-amines andother nervous system agents, whether sympathetic or parasympathetic,e.g., phenylethylamine (a stimulant), dopamine (a neurotransmitter anddopaminergic agent used, e.g., in the treatment of Parkinsonism orhyperprolactinemia), tyramine (a stimulant), L-DOPA (a dopamineprecursor used, for example, in the treatment of Parkinsonism); musclerelaxants, tranquilizers and antidepressants, e.g., benzodiazepinetranquilizers such as diazepam and oxazepam and phenothiazinetranquilizers such as carphenazine, fluphenazine and the like; mild andstrong analgesics and narcotics; sedatives and hypnotics; narcoticantagonists; vascular agents; stimulants; anesthetics; small peptides,such as the di-, tri-, tetra and pentapeptides, and other small 2-20amino acid unit containing peptides, e.g. the enkephalins (for example,Tyr-Gly-Gly-Phe-Leu), which, besides being analgesics, initiateepileptic activity in the brain at doses that are about tenfold lowerthan for effecting analgesic activity; larger peptides, such aspituitary hormones and related agents; growth-promoting substances;antiepileptic and anticonvulsant drugs generally, including hydantoinssuch as phenytoin and ethotoin, barbituates such as phenobarbital;hormones, such as the steroid hormones, e.g., estradiol, testosterone,17 α-ethylnyl testosterone (ethisterone), and the like (recent studieson histological mapping of hormone-sensitive and specific steroidbinding cells in the brain have underscored the importance of thesteroid action in the brain on sexual behavior); amphetamine-like drugs;anticancer and anti-Parkinsonism agents; antihypertensives; agents toenhance learning cpacity and the memory processes, including treatmentof dementias, such as Alzheimer's disease; antibacterials; centrallyacting hypotensive agents; centally acting prostaglandins, such as PGD₂; diagonstic agents, such as radio-pharmaceuticals; monoamine oxidase(MAO) inhibitor drugs; CNS or brain important/essential amino acids,such as tryptophan (which is an antidepressant as well as a nutrient);and any like centrally acting compounds. For the purposes of thisinvention, dopa or L-DOPA is not classified as an amino acid but ratheras a CNS amine and dopaminergic agent used, e.g. in the treatment ofParkinsonism.

Other illustrative ultimate species of centrally acting drug entitiesare: amphetamine, dextroamphetamine, levamphetamine, aletamine,cypenamine, fencamfamin, fenozolone, zylofuramine, methamphetamine,phenmetrazine and phentermine, which are sympathomimetic amines/cerebralstimulants and appetite suppressants; etryptamine, a cerebral stimulant;codeine, oxycodone, pentazocine, anileridine, hydromorphone, morphineand oxymorphone, which are narcotic analgesics; desipramine,nortriptyline, octriptyline, maprotiline, opipramol and protriptyline,which are cerebral stimulants/tricylic antidepressants of thedibenzazepine type used, e.g., in endogenous depressions; clonidine andmethyldopa, which are sympatholytic agents used, e.g., in hypertension;biperiden, cycrimine and procyclidine, which are centrally actinganticholinergics; tranylcypromine, a sympathomimetic cerebralstimulant/MAO inhibitor and antidepressant; acetophenazine,carphenazine, fluphenazine, perphenazine and piperacetazine, which arephenothiazine-type tranquilizers; benzoctamine, a sedative/musclerelaxant which structurally is an analogue of the phenothiazinetranquilizers; chlordiazepoxide, clorazepate, nitrazepam and temazepam,which are benzodiazepine-type tranquilizers; noracymethadol, a narcoticanalgesic of the methadone type; piminodine, a narcotic analgesic of themeperidine type; tracazolate, a sedative/hypotensive; prizidilol, acentrally acting hypotensive; sulpiride, an antidepressant/psychotropic;haloperidol and clopenthixol, which are tranquilizers; norepinephrine, asympathetic stimulant/adrenergic agent; nalorphine and naloxone,narcotic antagonists; hydralazine, a hypotensive; ethotoin,phenobarbital and aminoglutethimide, anticonvulsants; epinephrine, anadrenergic agent; ethamivan, a medullary stimulant; bemegride, abarbiturate antagonist; amiphenazole, a stimulant; iopydol, iodopyracet,idouppurate (o-iodohippuric acid), iodamide and iopanoic acid, which areradiodiagnostics; ephedrine, pseudoepherdrine, oxymetazoline andphenylephrine, which are sympathomimetic amines and decongestants;estradiol, estrone and estriol, the natural estrogens; amoxicillin,oxacillin, carbenicillin, benzylpenicillin, phenoxymethylpenicillin,methicillin, nafcillin, ticarcillin, bacampicillin, epicillin,hetacillin, pivampacillin, the methoxymethyl ester of hetacillin, andampicillin, which are penicillin-type antibiotics; amobarbital, asedative; trihexyphenidyl, a centrally acting antichloinergic;hydroxyzine, a tranquilizer; chlortetracycline, demeclocycline,minocycline, doxycycline, oxytertracycline, tetracycline andmethacycline, which are tetracycline-type antibiotics; flurazepam,bromazepam, demoxepam and lorazepam, benzodiazepine tranquilizers;phenytoin, an anticonvulsant; glutethimide, a mild hypnotic/sedative;clindamycin, lincomycin, nalidixic acid, oxolinic acid andphenazopyridine, antibacterials/antibiotics; bethanidine andguanethidine, hypotensives/sympatholytics; captopril, a hypotensive;methyprylon, a mild hypnotic; amedalin, bupropion, cartazolate,daledalin, difluanine, fluoxetine and nisoxetine, which are cerebralstimulants; propranolol, a β-blocker antihypertensive; dicloxacillin, apenicillin-type antibacterial; butalbital, a barbiturate sedative; GABA,γ-vinyl GABA, γ-acetylenic GABA, neurotransmitters for possible use inepilepsy; valproic acid and its metabolites such as5-hydroxy-2-n-propyl-pentanoic acid, 4-hydroxy-2-n-propylpentanoic acid,3-hydroxy-2-n-propylpentanoic acid, for use as anticonvulsants;valpromide, a valproic acid derivative for use as an anticonvulsant;apomorphine, a narcotic depressant/emetic which has been used in thetreatment of photosensitive epilepsy; pholcodine, a narcoticantitussive; methotrexate, mitoxantrone, podophyllotoxin derivatives(etopside, teniposide), doxorubicin, daunamycin and cyclophosphamide,anticancer/antitumor agents; methylphenidate, a stimulant; thiopental,an anesthetic; ethinyl estradiol and mestranol, estrogens; meptazinol,cyclazocine, phenazocine, profadol, metopon, drocode and myfadol, whichare narcotic analgesics; buprenorphine, nalbuphine, butorphanol,levallorphan, naltrexone, alazocine, oxilorphan and nalmexone, which arenarcotic antagonists or agonist-antagonists; norgestrel andnorethindrone, progestins; cephalothin, cephalexin, cefazolin,cefoxitin, moxalactam, ceforanide, cefroxadine and cephapirin,cephalosporin antibiotics; atenolol, nadolol, timolol and metoprolol,β-blockers/hypotensives; ACTH (corticotropin), a hormone whichstimulates glucocorticoid production; LHRH, a neurotransmitter whichstimulates secretion of the pituitary hormones, LH and FSH, and has beenused to induce ovulation as well as for fertility control/contraception;sulfadiazine and other sulfonamide antibiotics; ribavarin and acyclovir,antiviral agents; chlorambucil and melphalan, nitrogen mustard-typeanticancer/antitumor agents; methotrexate and aminopterin, which arefolic acid antagonist-type anticancer/antitumor agents; platinumcoordination complexes, i.e. cisplatin analogue-typeanticancer/antitumor agents; dactinomycin and mitomycin C, used incancer chemotherapy; thioguanine, a purine/pyrimidine antagonist used incancer treatment; vincristine and vinblastine, anticancer alkaloids;hydroxyurea and DON, anticancer urea derivatives; FSH, HCG and HCS,pituitary and nonpituitary gonadotropins, used, for example, in certainreproductive disorders; N,N'-bis(dichloracetyl)-1,8-octamethylenediamine(fertilysin), an agent for male fertility inhibition; levorphanol, anarcotic analgesic; benzestrol and diethylstilbestrol, syntheticestrogens; ethyl β-carboline-3-carboxylate, a benzodiazepine antagonist;furosemide, a diuretic/antihypertensive; dipyridamole and nifedipine,coronary vasodilators; and progabide, a GABA-agonist and prodrug ofGABA. Yet other ultimate species include non-steroidal antiinflammatoryagents/non-narcotic analgesics, e.g. propionic acid derivatives, aceticacid derivatives, fenamic acid derivatives and biphenylcarboxylic acidderivatives. Specific NSAID's/non-narcotic analgesics contemplated foruse herein include ibuprofen, naproxen, flurbiprofen, zomepirac,sulindac, indomethacin, fenbufen, fenoprofen, indoproxen, ketoprofen,fluprofen, bucloxic acid, tolmethin, alclofenac, fenclozic acid,ibufenac, flufenisal, pirprofen, flufenamic acid, mefenamic acid,clonixeril, clonixin, meclofenamic acid, flunixin, diclofenac,carprofen, etodolac, endosal, prodolic acid, sermetacin, indoxle,tetrydamine, diflunisal, naproxol, piroxicam, metazamide, flutiazin andtesicam.

Preferred classes of centrally acting drugs for use herein are thecentral neurotransmitters, steroids, anticancer and antitumor agents,antiviral agents, tranquilizers, memory enhancers, hypotensives,sedatives, antipsychotics and cerebral stimulants (especially tricyclicantidepressants). Among the neurotransmitters, there can be mentionedamino acids, such as GABA, GABA derivatives and other omega-amino acids,as well as glycine, glutamic acid, tyrosine, aspartic acid and othernatural amino acids; catecholamines, such as dopamine, norepinephrineand epinephrine; serotonin, histamine and tryptamine; and peptides suchas neurotensin, luteinizing hormone-releasing hormone (LHRH),somatostatin, enkephalins such as met⁵ -enkephalin and leu⁵ -enkephalin,endorphins such as γ-, α- and β-endorphins, oxytocin M and vasopressin.Synthetic and semi-synthetic analogues, e.g. analogues of LHRH in whichone or more amino acid(s) has/have been eliminated and/or replaced withone or more different amino acid(s), and which may be agonists orantagonists, are also contemplated, e.g. the primary and secondary amineLHRH analogues disclosed in U.S. Pat. Nos. 4,377,574, 3,917,825,4,034,082 and 4,338,305. Among the steroids, there can be mentionedanti-inflammatory adrenal cortical steroids such as hydrocortisone,betamethaxone, cortisone, dexamethaxone, flumethasone, fluprednisolone,meprednisone, methyl prednisolone, prednisolone, prednisone,triamcinolone, cortodoxone, fluroroctisone, flurandrenolone acetonide(flurandrenolide), paramethasone and the like; male sex hormones(androgens), such as testosterone and its close analogues, e.g. methyltestosterone (17-methyltestosterone); and female sex hormones, bothestrogens and progestins, e.g. progestins such as norgestrel,norethindrone, norethynodrel, ethisterone, dimethisterone,allylestrenol, cingestol, ethynerone, lynestrenol, norgesterone,norvinisterone, ethynodiol, oxogestone and tigestol, and estrogens suchas ethinyl estradiol, mestranol, estradiol, estriol, estrone andquinestrol and the like. Among the anticancer and antitumor agents,there can be mentioned Ara-AC, pentostatin (2'-deoxycoformycin), Ara-C(cytarabine), 3-deazaguanine, dihydro-5-azacytidine, tiazofurin,sangivamycin, Ara-A (vitarabine), 6-MMPR, PCNU, spiromustine,bisbenzimidazole, L-alanosine (6-diazo-5-oxo-L-norleucine), DON, L-ICRF,trimethyl, TMM, 5-methyltetrahydrohomofolic acid, glyoxylic acidsulfonylhydrazone, DACH, SR-2555, SR-2508, desmethylmisonidazole,mitoxantrone, menogarol, aclacinomycin A, phyllanthoside, bactobolin,aphidocolin, homoharringtonine, levonatradol, acivicin, streptozotocin,hydroxyurea, chlorambucil, cyclophosphamide, uracil mustard, melphalan,5-FUDR (floxuridine), vincristine, vinblastine, cytosine arabinoside,6-mercaptopurine, thioguanine, 5-azacytidine, methotrexate, adriamycin(doxorubicin), daunomycin (daunorubicin), largomycine polypeptide,aminopterin, dactinomycin, mitomycin C, and podophyllotoxin derivatives,such as etoposide (VP-16) and teniposide. Among the antiviral agents,there can be mentioned ribavarin; acyclovir (ACV); amantadine (also ofpossible value as an anti-Parkinsonism agent); diarylamidines such as5-amidino-2-(5-amidino-2-benzofuranyl)indole and4',6-diimidazolino-2-phenylbenzo(b)thiophene; 2-aminooxazoles such as2-guanidino-4,5-di-n-propyloxazole and 2-guanidino-4,5-diphenyloxazole;benzimidazole analogues such as the syn and anti isomer of6[[(hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1H-benzimidazol-2-amine;bridgehead C-nucleosides such as5,7-dimethyl-2-β-D-ribofuranosyl-s-triazole(1,5-a)pyrimidine; glycosidessuch as 2-deoxy-D-glucose, glucosamine, 2-deoxy-2-fluoro-D-mannose and6-amino-6-deoxy-D-glucose; phenyl glucoside derivatives such asphenyl-6-chloro-6-deoxy-β-D-glucopyranoside;(S)-9-(2,3-dihydroxypropyl)adenine; 6-azauridine; idoxuridine;trifluridine; BDVU (bisdihydroxyvinyluridine); and5,6-dichloro-1-β-D-ribofuranosylbenzimidazole. Among the tranquilizers,there can be mentioned benzodiazepine tranquilizers, such as diazepam,oxazepam, lorazepam, chloridazepoxide, flurazepam, bromazepam,chlorazepate, nitrazepam and temazepam; hydantoin-typetranquilizers/anticonvulsants such as phenytoin, ethotoin, mephenytoin;phenothiazine-type tranquilizers such as acetophenazine, carphenazine,fluphenazine, perphenazine and piperacetazine; and others. Among thehypotensives, there can be mentioned clonidine, methyldopa, bethanidine,debrisoquin, hydralazine, and guanethidine and its analogues. Among thesedatives, tranquilizers and antipsychotics, there can be mentioned themany specific compounds of this type disclosed above, especially thephenothiazines and benzodiazepines and their analogues. Among thecerebral stimulants, there also can be mentioned the many specificcompounds set forth hereinabove, particularly the sympathomimeticamine-type cerebral stimulants and the tricyclic antidepressants,especially preferred tricyclics being the dibenzazepines and theiranalogues.

Also illustrative of the centrally acting drug species contemplated bythis invention are centrally active metabolites of centrally actingdrugs. Such metaolites are typified by hydroxylated metabolites oftricyclic antidepressants, such as the E- and Z-isomers of10-hydroxynortriptyline, 2-hydroxyimipramine, 2-hydroxydesipramine and8-hydroxychlorimpramine; hydroxylated metabolites of phenothiazinetranquilizers, e.g. 7-hydroxychlorpromazine; and desmethyl metabolitesof N-methyl benzodiazepine tranquilizers, e.g. desmethyldiazepam. OtherCNS active metabolites for use herein will be apparent to those skilledin the art, e.g. SL 75102, which is an active metabolite of progabide, aGABA agonist. Typically, these CNS active metabolites have beenidentified as such in the scientific literature but have not beenadministered as drugs themselves. In many cases, the active metabolitesare believed to be comparable in CNS activity to their parent drugs;frequently, however, the metabolites have not been administered per sebecause they are not themselves able to penetrate the blood-brainbarrier.

As indicated hereinabove, diagnostic agents, includingradiopharmaceuticals, are encompassed by the expression "centrallyacting drug" or the like as used herein. Any diagnostic agent which canbe derivatized to afford a compound of formula (I) which will penetratethe BBB and concentrate in the brain in its quaternary form (II) and canbe detected therein is encompassed by this invention. The diagnostic maybe "cold" and be detected by X-ray (e.g. radiopaque agents) or othermeans such as mass spectrophotometry, NMR or other non-invasivetechniques (e.g. when the compound includes stable isotopes such as C13,N15, O18, S33 and S34). The diagnostic alternatively may be "hot", i.e.radiolabeled, such as with radioactive iodine (I 123, I 125, I 131) anddetected/imaged by radiation detection/imaging means. Typical "cold"diagnostics for derivation herein include p-iodohippuric acid,iothalamic acid, iopydol, iodamide and iopanoic aicd. Typicalradiolabeled diagnostics include diohippuric acid (I 125, I 131),diotyrosine (I 125, I 131), o-iodohippuric acid (I 131), iothalamic acid(I 125, I 131), thyroxine (I 125, I 131), iotyrosine (I 131) andiodometaraminol (I 123), which has the structural formula ##STR15## Inthe case of diagnostics, unlike the case of drugs which are for thetreatment of disease, the "locked in" quaternary form will be the formthat is imaged or otherwise detected, not the original diagnosticitself. Moreover, any of the centrally acting drugs encompassed by thisinvention which are intended for the treatment or prevention of medicaldisorders but which can be radiolabeled, e.g. with a radioisotope suchas iodine, or labeled with a stable isotope, can thus be converted to adiagnostic for use herein. Put another way, any compound of formula (I)of this invention which can have incorporated into its structure such aradioactive or stable isotope [either directly or through incorporationof the isotope into the structure of the corresponding compound offormula (II)] can be used for diagnostic purposes.

It will be apparent from the known structures of the many drug speciesexemplified above, that in many cases the selected drug will possessmore than one reactive functional group, and, in particular, that thedrug may contain hydroxyl or carboxyl or amino or other functionalgroups in addition to the groups to which the carrer will be linked, andthat these additional groups will at times benefit from being protectedduring synthesis and/or during administration. The nature of suchprotection is described in more detail below. Obviously, such protecteddrug species are encompassed by the definition of "drug" set forthhereinabove.

It too will be appreciated that by "dihydropyridine carrier" or "[DHC]",there is intended any nontoxic carrier moiety comprising, containing orincluding the dihydropyridine nucleus, whether or not a part of anylarger basic nucleus, and whether substituted or unsubstituted, the onlycriterion therefor being capacity for BBB penetration and in vivooxidation thereof to the corresponding quaternary pyridinium saltcarrier [QC]⁺. As aforesaid, the ionic pyridinium salt drug/carrierprodrug entity [D--OC]⁺ which results from such in vivo oxidation isprevented from efflux from the brain, while elimination from the generalcirculation is accelerated. Subsequently, the covalent or equivalentbond coupling the drug species [D] to the quaternary carrier [QC]⁺ ismetabolically cleaved, which results in sustained delivery of the drug[D] in the brain and facile elimination of the carrier moiety [QC]⁺.Such "covalent or equivalent bond" between the drug and the quaternarycarrier can be a simple direct chemical bond, e.g., an amide, an ester,or any other like bond, or same can even be comprised of a linking groupor function, e.g., a thiazolidine bridge or a peptide linkage, typicallynecessitated when the drug species is not susceptible to direct chemicalcoupling to either the dihydropyridine carrier or the quaternarycarrier. Nonetheless, the bond in the formulae [D--QC]⁺ and [D--DHC] isintended to be, and is hereby defined as inclusive of all suchalternatives. And the cleavage of the [D--QC]⁺ prodrug to sustainedlydelivery the drug species [D] in the brain with concomitant facileelimination of the carrier moiety [QC]⁺ is characteristically enzymaticcleavage, e.g., by esterase, amidase, cholinesterase, hydrolytic enzyme,or peptidase, albeit any type of in brain cleavage which might result,whether enzymatic, metabolic or otherwise, of course remains within theambit of this invention. Thus, the drug release rate controllingparameter of the subject pro-prodrugs is imparted simply via thecleavable bonding between drug and carrier, and not by any release ratecontrolling substituent(s).

The expression "non-toxic pharmaceutically acceptable salts" as usedherein generally includes the nontoxic salts of compounds of formula(I), wherein [D] is a centrally acting drug species and [DHC] is thereduced, biooxidizable, blood-brain barrier penetrating form of adihydropyridine⃡pyridinium salt redox carrier, formed with nontoxic,pharmaceutically acceptable inorganic or organic acids XH. For example,the salts include those derived from inorganic acids such ashydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric andthe like; and the salts prepared from organic acids such as acetic,propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric,ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic,benzoic, salicylic, sulfanilic, fumaric, methanesulfonic,toluenesulfonic and the like. The expression "anion of a non-toxicpharmaceutically acceptable acid" as used herein, e.g. in connectionwith structure (II), is intended to include anions of such inorganic ororganic acids HX.

In one embodiment according to this invention, simple nontoxic carriersystems [D--QC]⁺ ⃡[D--DHC] are envisaged, utilizing a wide variety ofmodels for D, such as those above outlined. Representative such carriersystems and models are: ##STR16## wherein R₂ is simply alkyl, e.g., CH₃,or benzyl, albient virtually any other effective substituent isintended. (As depicted above, the isomeric dihydropyridine structuredepends on the position of the substituent relative to the pyridinenitrogen.) Exemplary of such simple carrier systems are N-alkylnicotinamide and nicotinate ester derivatives, tethered to such drugspecies as dopamine, melphalan and testosterone. The trigonelline(N-methylnicotinic acid) system is quite effective as a carrier; it alsois readily eliminated from the circulation and is virtually non-toxic.

Indeed, the present invention provides a flexible arsenal ofdihydropyridine⃡pyridinium salt redox carriers for thesite-specific/sustained delivery of virtually any centrally acting drugspecies to the brain. Moreover, any dihydropyridine/pyridinium saltredox carrier entity is contemplated and intended hereby generically,and any such carrier moiety need not be, and is not, derivatized with adrug release rate controlling substituent critically tailored to meet,or be coordinated with, the chemical nature and deliveery requirementsof the particular drug species sought to be preferentially administeredto the brain. As utilized herein, the term "carrier" is to be understoodas connoting just such a non-derivatized, non-drug/carrier coordinatedentity, for consistent herewith it is the "carrier" entity itself andnot the nature of any activity or release rate controlling/modifyingsubstituent which is responsible for providing the desiredbrain-specific result.

Additional examples of such redox carriers include the quaternarypyridinium alcohols (1), the analog isoquinoline acid and alcoholsystems (2), and multicharged delivery forms, exemplified by structure 3(D represents drug, Z a colvant link) and obviously the correspondingdihydro forms. ##STR17##

Yet other redox carriers include those comprising an acidic chaindirectly linked to the heterocyclic nitrogen, in quaternary or tertiaryamine form. Also the hydroxide type carriers, e.g., the glucosamineanalog indicated below. Representative are: ##STR18##

Preparation: ##STR19## Method of: H. Lattre et al., Annalen, 579, 123(1953). ##STR20##

Generally preferred dihydropyridine⃡pyridinium salt redox carriers foruse in the present invention include the following (where D representsthe drug), and obviously the corresponding dihydro forms:

(a) the pyridinium systems ##STR21## in which the depicted substituentis in the 2-, 3- or 4- position, and R₁ is C₁ -C₇ alkyl or C₇ -C₁₀aralkyl, preferably methyl or benzyl;

(b) the pyridinium system ##STR22## in which R₃ is C₁ to C₃ alkylene,i.e., (CH₂)_(n) where n=1-3;

(c) the isoquinolinium and quinolinium systems ##STR23## in which R₁ isdefined as above; and

(d) the quinolinium andisoquinolinium systems ##STR24## in which R₃ isdefined as above. The corresponding dihydro forms of the foregoingpreferred pyridinium salts are depicted below, wherein the position andidentity of the structural variables are as indicated above: ##STR25##

In accord with the present invention, the sustained delivery of a drugto the brain in sufficient concentrations to achieve the desiredpharmacological effect can be accomplished with much lowerconcentrations in the peripheral circulation and other tissues. Thepresent invention of course will allow such treatment of any otherorgans or glands in which sufficient drug accumulates. Thus, forexample, it is expected that the quaternary form (II) which is locked inthe brain will be locked in the tests as well. See applicant's earliercopending Application Ser. No. 475,493.

The novel chemical delivery system of this invention begins with thepreparation of the novel quaternary intermediates of formula (II). Thepreparation of those intermediates will be tailored to the particulardrug portion and carrier portion to be combined, and especially to thenature of the chemical bond between them, e.g. whether the linkage is anester or amide linkage, as well as to the presence or absence of otherreactive functional groups (amino, mercapto, carboxyl, hydroxyl,hydroxy) in either the drug or carrier portion. Typicaly, if such otherreactive groups are present, they are found in the drug portion. In anyevent, when such groups are present and it is desired to protect them, astep that introduces appropriate protecting groups can be incorporatedat a suitable stage of the synthetic pathway. Typical protective groupsare well known in the art and have been defined hereinabove. Whencarbonate protecting groups for hydroxy radicals are desired, the stepof introducing the protecting groups will involve reacting the alcoholwith a halocarbonate of the type ROCOCl or ROCOBr (formed by reaction ofROH with COCl₂ or COBr₂, R typically being lower akyl). For acylprotecting groups, the alcoholic hydroxyl is reacted with an acylhalides RCl or RBr, R being e.g., --COCH₃ or --COC(CH₃)₃. Yet otherreaction schemes and reactants will be readily apparent to those skilledin the art, as well the appropriate means for removing such protectivegroups after they have achieved their function and are no longer needed.As already explained above, carboxyl and hydroxyl protecting groups aretypically retained in the compounds of formulas (I) and (II) rather thanbeing removed, so that they can perform their protective function invivo as well.

In forming the intermediates of formula (II), at least one amino,hydroxyl, mercapto, carboxyl, amide or imide group in a drug will bebonded to [QC⁺ ], the hydrophilic, ionic pyridinium salt form of adihydropyridine⃡pyridinium salt redox carrier.

In a preferred embodiment of the present invention, sustained deliveryof drug to the brain in pharmacologically effective concentrations hasnow been demonstrated, paralleled with much lower concentrations in theperipheral circulation and other tissues, utilizing dopamine as thetarget drug species and a trigonelline-type carrier system, with thecatechol moiety thereof in certain instances being acylated, e.g.,acetylated or pivalylated. According to Scheme 3 which follows, onespecific delivery system for dopamine, compound 5, on administratio(e.g., by injection) is distributed throughout the body and by reason ofits lipophilic character facilely penetrates the blood-brain barrier andenters the CNS. Following oxidation both in the brain and in the othertissues, the corresponding hydrophilic quaternary salt (6) is formed.The quaternary salt 6 is essentially "locked in" the brain and itsconcentration is considered to increase with time until reaching amaximum, which depends primarily on the relative rates of entrance ofthe dihydro compound (5) to the brain (K₁) as compared to K₂ to theother tissues, the rate of oxidation of the dihydro form to thequaternary (K₃ and K₇) and the rates of its disappearance from the brain(K₄ +K₅). At the same time, the very water soluble quaternary forms) 6is/are excreted readily via the kidney and the liver (K₈ >>K₄).Derivatives 6 are considered to be essentially inactive forms (K₈ >>K₉),and thus systemic activity/toxicity is minimized. Hence, theconcentration of 5 and 6 in the blood rapidly increases. The ratio ofthe quateernary salt 6 in the brain relative to the blood increases tothe point where 6, or metabolites thereof, can only be found in thebrain. The quaternary 6, whether in the brain, blood or other tissues,is deemed to release dopamine and the non-toxic compound, trigeonelline,depending upon the rates of site-specific conversion of the precursor 6to the drug at each of these sites. The concentration of any releaseddopamine at any time is much higher in the brain than in the blood orother tissues. Also, as the enzymatic transformation of the quaternaryprecursor 6 to the drug (dopamine) is relatively slow, same permits asustained release of dopamine. Too, the simultaneousprotection/lipophilic derivatization of the catechol system in dopaminehas also now been demonstrated.

It will be appreciated that a compound of formula (I), suc as compound5, may be administered as the free base, e.g. as depicted in Scheme 3,or in the form of a non-toxic pharmaceutically acceptable salt thereof,i.e., a salt which can be represented generally by the formula

[D--DHC].HX

and more specifically with respect to Scheme 3 by the formula ##STR26##wherein HX is as defined befoe; and that, regardless of the actual formin which the compound is administered, it will be converted in vivo to aquaternary salt of formula (II), i.e. a salt of the compound 6 type, theanion X⁻ being an anion present in vivo. It is not necessary that theanion be introduced as part of the compound administered. And even whenthe compound of formula I (e.g. compound 5) is used in its salt form,the anion of the formula (II) compound (e.g. of compound 6) is notnecessarily the same as that present in the formula (I) compound. In anyevent, the exact identity of the anionic portion of the compound offormula (II), is immaterial to the in vivo transformation of (I) to(II), e.g. the depicted enzymatic transformation. ##STR27##

With specific reference to the immediately above, the1,4-dihydropyridine derivatives (5) were prepared as in the followingScheme 4: ##STR28##

Similar schemes can be shown for the preparation of the other dopaminederivatives of the invention. The step which introduces the protectinggroups is of course only required when it is desired to protect thecatechol hydroxyl groups. Moreover, when carbonate rather than acylprotecting groups are desired, the step of introducing the protectinggroups will involve reacting the catechol with a halocarbonate of thetype Y'OCOCl or Y'OCOBr (formed by reaction of Y'OH with COCl₂ orCOBr₂), rather than with an acyl halide YCl or YBr, Y and Y' being asgenerically defined hereinabove. Also, the order of steps shown inScheme 4 may be altered; quaternization, followed by reduction, need notbe in the final two steps but may be carried out earlier in the reactionsequence. Yet other reaction schemes and reactants (e.g., using ananhydride rather than an acyl halide to convert 7 to 8) will be readilyapparent to those skilled in the art, Scheme 4 being simply a preferredapproach for the specific compounds there depicted. Variations of thisapproach are likewise applicable to preparing derivatives of otherhydroxy-containing amines.

In an attempt to ascertain whether any biotransformation of the freecatechol is taking place by COMT (catechol-O-methyltransferase) eitherbefore or after oxiation, the possible O-methyl metabolites (9 and 10)were synthesized separately following Scheme 4 with 3-methoxytyraminehydrochloride as the starting material. ##STR29##

The stability of the 1,4-dihydropyridine derivatives (5) was determinedin the presence of the oxidizing agents, alcoholic AgNO₃ and hydrogenperoxide. The in vitro rates of oxidation of the 1,4-dihydropyridinederivative (5c) in 80% plasma, 20% brain homogenate, 20% liverhomogenate and in whole blood were determined.

The dihydropyridine derivative (5c) was then selected for the in vivostudy. A solution in DMSO (dimethylsulfoxide) was injected through thejugular vein to a group of male Sprague-Dawley rats which were thensacrificed at various time intervals; their blood and brains wereanalyzed for the quaternary percursor of dopamine (6a). The in vivodopaminergic activities of the selected compounds 5c vs. 6a were thendetermined.

Consistent with the above, it was found that N-nicotinoyldopamine (7)could be obtained in good yields by coupling dopamine hydrobromide withnicotinic acid in pyridine as a solvent and withdicyclohexylcarbodiimide as the coupling agent. Attempts to prepare 7 byusing dopamine free base were largely unsuccessful. As for the catecholprotecting groups, the acetyl and pivalyl moieties were selected due totheir rather different steric and partitioning parameters. Acylationcould be accomplished with the acyl chlorides by using conventionalmethods. Reduction of the quaternaries (6a-c and 9) was accomplished byusing sodium dithionite in mildly basic aqueous solution, (NaHCO₃). Itwas observed that the dihydro compound obtained in the case of thequaternary 6b gave a faint green color with ferric ions, indicatingpartial hydrolysis of at least one of the acetyl moieties duringreduction, even in the cold, weakly basic solution used as a medium. Thedihydropyridine derivatives isolated (5a-c and 10) were determined tohave the expected 1,4-dihydropyridine structure, based on their NMR andUV spectra. Attempts to prepare the β-protonated enamine salts of theisolated dihydro derivatives were also largely unsuccessful, due to acidcatalyzed addition reactions. The 1,4-dihydropyridine derivatives (5a-c)were found to be relatively stable towards oxidation. Compound 5c wasquantitatively oxidized to the corresponding quaternary salt 6c by H₂ O₂or alcoholic AgNO₃ solution.

The diacetyl derivatives (5b and 6b) appeared to be labile to hydrolysisand therefore were not pursued in vitro. The dipivalyldihydro derivative(5c) was thoroughly investigated for its in vitro rates of disappearanceand metabolic degradation in various biological fluids. It is evidentthat 5c represents a rather complex case, as besides oxidation, atwo-step hydrolysis will also take place. Scheme 5 illustrates theinterconversion of the possible components. ##STR30##

FIGS. 1-4 illustrate the results of such an investigation. The apparenthalf-lives for the disappearance of 5c in biological fluids at 37° C.were calculated. Although the process does not truly follow first orderkinetics, the data fit very closely a pseudo first order process (FIG.5). The obtained values, 51 min (80% plasma), 17 min (20% brainhomogenate), 18 min (whole citrated blood) and 6 min (20% liverhomogenate), reflect an acceptable stability of the dihydro derivative5c. The disappearance of 5c is accompanied by formation of somemonoester (11) and dihydroxy dihydro form (5a) in all the media exceptthe liver homogenate. The rate of hydrolysis of the first ester moietyis faster than the second and a reasonable amount of monoester 11 buildsup with time. The monohydroxy quaternary 12 could not be detected exceptin the blood as a very small peak which does not change significantlywith time. A steady increase in the concentration of the dihydroxyquaternary 6a was observed in all media except liver homogenate. Thus,it is established that this derivative, 6a, is forming as the mainproduct of the various interconversion routes and it is the directprecursor thus concluded to be locked in the brain in the in vivoexperiment. No formation of the methoxy derivatives 9 and 10 could bedetected in any of the biological fluids studied; 5a and 6a do notappear to be good substrates for COMT.

The first objective of the in vivo studies was to trace the appearanceand disappearance of 6a in blood and brain following administration of5c. FIG. 6 summarizes such results, and is consistent with the mechanismshown in Scheme 3. After one single injection of the 1,4-dihydropyridinederivative 5c to the rat, the dihydroxy quaternary 6a (ion), which isthe only detectable derivative, could be seen to appear and then todisappear quickly from the blood, with a half-life of 27 min. On thecontrary, the concentration of 6a (ion) is increasing in the brainsteadily, reaching a maximum at about 30 min following administration.The descending portion indicates a half-life of disappearance from thebrain of about 3.2 h. No formation of O-methyl metabolites (9, 10) couldbe detected in the brain. This confirms the in vitro results that 6a (or5a) is not a good substrate for COMT.

To determine whether dopamine itself was finally released in the brainupon completion of the aforesaid complex delivery process, 5c wasadministered intrajugularly and changes in brain-dopamine concentrationsfollowing that administration were studied. Some of the rats showed upto threefold increase in the dopamine concentrations, others practicallynone. Since it is possible (and even desired) that the intrinsic brainmetabolism of the dopamine does not permit significant build-up of itsconcentration, specific pharmacologic activity was investigated, usingchange in the in vivo prolactin secretion. It is known that dopamine andits agonists decrease prolactin secretion following their binding tostereospecific receptors located on lactophors in the anterior pituitary(AP) gland [G. P. Mueller, J. W. Simpkins, J. Meites and K. E. Moore,Neuroendocrinology, 20, 121 (1976); W. Wuttke, E. Cassell and J. Meites,Endocrinology, 88, 737 (1971); J. A. Clemens, E. B. Smalstig and C. J.Shaar, Acta Endocrinol., 79, 230 (1975)]. This effect is dose-dependentand it can also be observed in vitro, incubating anterior pituitarieswith dopamine or its agonists [R. M. MacLeod in "Frontiers inNeuroendocrinology", Ed. L. Martini and W. F. Ganong, Raven Press].

It was then determined that exposure of male rats to 17-β-estradiol fortwo days elevated serum prolactin levels to greater than 150 ng/ml.Intravenous administration of 5c caused a 79% decrease in serumprolactin concentrations and this dramatic reduction was maintainedthrough 120 min after treatment. In contrast, 6a had no significanteffect on the serum prolactin concentrations by 15 min, and caused a 67%reduction by 30 min. Thereafter, serum prolactin levels increasedprogressively to levels which are not significantly different fromvehicle injected controls, by 60 and 120 min. These results aresummarized in FIG. 7. The rapid onset and prolonged inhibitory effectsof 5c on prolactin secretion is consistent with the time course of theappearance of 6a in the brain following administration of 5c. The"trapping" of 6a in the brain subsequent to I.V. injection of 5cprovides a constant source of a potent dopaminergic agent, eitherdopamine or 6a itself. The significantly lower effect of 6a whenadministered I.V. does not unequivocally clarify which alternative isthe more responsible. This was resolved by in vitro comparison of therelative activities of dopamine versus 6a.

Fresh anterior pituitaries obtained from female rats were incubated withvarious concentrations of dopamine (DA) and 6a, repsectively, and theireffects on the rate of release of prolactin were measured. It was foundthat at 2×10⁻⁸ M concentrations, neither DA nor 6a had any effect, butat 2×10⁻⁷ M, DA caused a 57% reduction of the prolactin rate secretion,while 6a had no effect. These results are summarized in the followingTable I.

                                      TABLE I                                     __________________________________________________________________________    Comparative in vitro activity of 6a vs. dopamine.sup.a                        Prolactin ng/mg./h.sup.b                                                      Dopamine (DA).sup.c     6a.sup.d                                                   DA          DA          6a          6a                                   Control                                                                            2 × 10.sup.-8 M                                                                Control                                                                            2 × 10.sup.-7 M                                                                Control                                                                            2 × 10.sup.-8 M                                                                Control                                                                            2 × 10.sup.-7                  __________________________________________________________________________                                             M                                    344 ± 50                                                                        355 ± 67                                                                          282 ± 34                                                                        121 ± 38*                                                                         342 ± 38                                                                        386 ± 29                                                                          250 ± 30                                                                        277 ± 32                          __________________________________________________________________________     .sup.a On freshly obtained anterior pituitary (AP) at 37° C. All       values are average of 9 separate APS.                                         .sup.b Prolactin release rate of the incubated APS.                           .sup.c Weight of the APS: Control 4.6 ± 0.2 mg. DA treated 4.5 ± 0.     mg.                                                                           .sup.d Weight of the APS: Control 4.6 ± 0.3 6a treated 4.7 ± 0.4        *P < 0.05                                                                

These results indicate that if 6a has any activity, it must besignificantly less than that of DA. Based on the delayed onset of theactivity when 6a was adminitered I.V. and considering the in vitroresults, it logically follows that the high and prolonged activity ofthe 6a locked in the brain following administration of 5c is due to thefact that 6a is slowly releasing the active DA in the brain.

Accordingly, provided hereby is a potent, brain-specific dopaminergicagent comprising a lipophilic dihydropyridine carrier-type chemicaldelivery system of dopamine ["pro-prodrug" or "pro-pro-prodrug" in thecase of the catechol protectiv group(s)], which penetrates the BBBpassive transport. The rapid oxidation in the brain of the carriermoiety to the corresponding quaternary pyridinium salt results in anactivated amide of dopamine. The oxidation process is much faster thanamide cleavage of the beginning compound 5 or of 6. Moreover, the ionicnature of the activated quaternary salt results in a significantslowdown of the efflux of this specific form through the BBB, resultingin a selective concentration enhancement of the precursor 6a in thebrain. Too, brain-specific dopaminergic activity is assured, logicallyas dopamine is released from this activated form upon hydrolytic,enzymatic or metabolic cleavage, as is facile excretion of the carriermoiety from the brain.

In yet another embodiment of the invention, like synthesis of theanalogous tyramine system has been carried out, and the correspondingdeterminations made. Such tyramine system is represented as follows:##STR31##

Naturally, selection of the particular dihydropyridine ⃡ pyridinium saltredox carrier to be used will depend on the chemical structure of thespecific drug involved. And not only should the nature of the functionalgroup which is to be linked to the carrier system be considered inselecting the carrier, but the manner in which the ultimate compound isprepared should be tailored to the presence of any other reactive groupsin the molecule. The following examples of specific drug/carriercombinations and their manner of synthesis are set forth for the purposeof illustration only and are not to be considered limitative in any waywhatsoever.

Thus, in one specific illustration, the selected drug is testosteroneand the selected carrier system is trigonelline ⃡dihydrotrigonelline;according to this embodiment, testosterone is reacted with nicotinoylchloride, the resultant ester is then quaternized with methyl iodide,and the quaternary iodide is then reduced with Na₂ S₂ O₄ to afford thetestosterone-CDS (chemical delivery system) ##STR32## Other steroids canbe similarly derivatized, e.g., 17α-ethynyltestosterone, estradiol andthe like.

Another specific illustration involves selecting melphalan and the sametype of carrier system as above, but forming an amide rather than anester linkage. Thus, melphalan is converted to its hydrobromide, whichis reacted with nicotinic acid to afford the amide having the formula##STR33## which can be esterified, if desired (to increase lipoidalcharacteristics), followed by, when the ethyl ester is prepared,quaternizing same with methyl iodide to form ##STR34## which can then bereduced to afford the melphalan-CDS ##STR35## As one of severalalternative schemes, melphalan can be derivatized by first esterifyingit, e.g., to convert the carboxy function to the ethyl ester, thenreacting the resultant melphalan ethyl ester with nicotinoyl chloride toform the amide of the formula ##STR36## which can then be quaternizedand the quarternary salt subsequently reduced as indicated above toafford to same melphalan-CDS as depicted above.

Yet another specific illustration utilizes chlorambucil as the targetdrug, in which case the desired nicotinic acid carrier system is linkedto the drug via a bridging group. Thus, nicotinic acid can be reactedwith an appropriate di- or polyhydroxy compound such as ethylene glycol,propylene glycol or inositol and the resultant intermediate is linkedvia its free hydroxy group(s) to the carboxylic acid function ofchlorambucil. That intermediate is then quaternized and the quaternarysalt is reduced to afford the chlorambucil-CDS. In the case of nicotinicacid and ethylene glycol starting materials, the chlorambucil-CDS hasthe formula ##STR37##

On the other hand, when a polyhydroxy compound is reacted with nicotinicacid in the first step, a variety of products are possible. Thus, forexample, when inositol is used, the final product may contain anywherefrom 1 carrier/5 drug residues to 5 carrier/1 drug residue. In the caseof the inositol trinicotinate intermediate ##STR38## conditions forreacting same with chlorambucil can be selected so that one, two orthree of the hydroxy functions react with the acid. When all threehydroxys react, the ultimate chlorambucil-CDS has the formula ##STR39##and contain 3 drug residues and 3 carrier groupings.

As another example, methotrexate, which has the structural formula##STR40## can be derivatized similarly to chlorambucil via its carboxyfunction(s), e.g., utilizing the inositol trigonellinates or aglucosamine analogue.

As a further example, podophyllotoxin and its derivatives can be linkedto a carrier system of this invention. These drugs can be represented bythe structural formula ##STR41## and can be derivatized by reacting thehydroxy group in podophyllotoxin (R₄ ═OH) or the hydroxy groups in theglycosidic portions in R₄ with acidic type redox carriers, e.g., in amanner analogous to the testosterone-CDS depicted above. Known cisplatinanalogues, in which typically the amino groups have been replaced withorganic radicals, can be similarly derivatized according to theinvention, the method of choice depending on the nature of thefunctional groups in the organic radicals.

Similarly, syntheses and like determinations as regards the redoxcarrier-linked enkephalins can be carried out. First synthesized is theknown leucine enkephalin XI. The quaternary pyridinium analog XII, thecorresponding O-benzyl ether XIII and the amide XIV are nextsynthesized. ##STR42##

The O-benzyl pentapeptide ethyl ester derivative of XI is synthesizedsequentially and then coupled with nicotinic acid, followed bymethylation. Alternate methods involve introduction of carrier at anearlier stage in the synthesis. The reduction of XII and XIII results ina mixture of products due to the base sensitivity of the ester. Likewiseprepared are the corresponding leucinol trigonelline ester XV and itsdihydro derivative XVI. ##STR43## Thus, the site-specific brain deliveryof the enkephalins for the treatment of epilepsy is establishedconsistent with the Scheme 1, as is their analgesic activity.

Similarly, as regards the benzodiazepine tranquilizers, e.g.: ##STR44##This reaction scheme utilizes conventional opening of the 7-member ring,accompanied by coupling of the drug to the carrier. The following drugscan be similarly derivatized to the corresponding dihydro derivatives:##STR45##

Yet another example of tailoring chemical synthesis to the particulardrug involved is shown in Scheme 6 below, which depicts synthesis of aradio-diagnostic, I 123 labeled metaraminol, carrier system. Note thatin the case of radiolabeled compounds, the method of choice generallyinvolved introducing the radioactive element toward the end of thereaction sequence, rather than using the radiolabeled parent drug itselfas the starting material. ##STR46##

And in another preferred embodiment of the invention, there is providedthe effective, selective and nontoxic treatment of epilepsy, based uponthe mechanism illustrated in Scheme 1. Indeed, commencing from the"GABA-hypothesis" of epilepsy, the brain-specific, enhanced andsustained release of GABA (γ-aminobutyric acid) itself, and variousother compounds either directly or indirectly affecting theconcentrations of GABA in the brain, is circumscribed consistentherewith. Model compounds include carboxylic acids, most specificallyvalproic acid, as well as some of the GABA analogs which inhibitirreversibly the GABA-T, such as γ-vinyl and/or γ-acetylenic GABA. Usingthe aforesaid trigonelline (N-methylnicotinic acid)⃡dihydrotrigonellinesystem, for example, the selected compounds can be effectively deliveredper Scheme 1. Thus, representative target compounds are thedihydropyridine carrier-drug combinations 1 and the correspondingpyridinium carrier-drug species, for example, GABA and its esters:##STR47## Related derivatives for γ-vinyl and γ-acetylenic GABA are:##STR48## In the case of valproic acid, other alternatives are:##STR49##

In another embodiment of like delivery system, applicable for both theGABA and related compounds and for the carboxylic acids, or for anyother drug species to be linked to such a carrier, either directly orindirectly, i.e., mediated by a carboxylic acid, e.g., succinic acid, orother linkage, provided is a mono- or poly-substituted nontoxic polyol(such as inositol or sugars) having the trigonelline⃡dihydrotrigonellinesystem and the compounds to be delivered linked to the same molecule asexemplified by the GABA case (5⃡5a) and valproic acid (6⃡6a): ##STR50## R₄=H, GABA or valproic acid, but at least one of R₄ is: ##STR51## R₄ canbe partically replaced by additional GABA or valproic acid, changing thecarrier/drug ratio as necessary. Some of the valproic acid metabolitescan be coupled with carriers of the redox type, via the various hydroxygroups formed during the oxidative degradation: ##STR52## Illustrativeexamples are the corresponding derivatives of the 5-, 4-, and3-hydroxy-2-n-propyl pentanoic acid derivatives. Additional carriersystems, such as the isoquinoline⃡dihydroisoquinoline system, can also bedeveloped consistent herewith.

Moreover, based upon the observation that NADH content is significantlyreduced in epileptic and like seizures, the use of the subject redoxsystem (in reduced form) will bias the NAD⃡NADH balance towards NADHduring the dihydro carrier→quaternary transformation. Also, thebrain-specific delivery of small peptides consistent herewith, e.g, theenkephalins, which have been found to initiate epileptic, seizures, hasled to the design of a variety of long lasting potent antagonists.

And the subject chemical delivery system is also useful for the deliveryof other anticonvulsants in a sustained, brain-specific fashion, e.g.,the benzodiazepines and hydrantoins, and those compounds, likeapomorphine, which are useful in the treatment of photosensitiveepilepsy.

It will of course be appreciated in the immediately above regard thatthe drug treatment of epilepsy has always posed formidable problems.There are many different anticonvulsants available, some more specificfor different types of seizures. Indeed, there exist a wide variety ofopinions as to which is the most suitable drug for any particular typeof seizure, and drug mixtures are typically employed. An inevitableresult of the traditional therapy is the development of chronictoxicity, but such result is conspicuously avoided according to thepresent invention.

It too will be appreciated that the desired therapeutic effects of allantiepileptic agents investigated, as well as their undesired toxiceffects, reflect a statistically significant correlation with the druglevels in plasma. This correlation is based upon a close relationshipbetween the drug concentrations in plasma and brain tissue. Hence, aprimary attribute of this invention is to enable attainment of high andsustained brain levels of the selected active agents, essentiallyagainst the plasma-brain concentration gradient and independent of thedrug concentration in the blood.

GABA and related compounds are logical candidates. It has been shownthat GABA neuron function is impaired in at least certain types of humanepilepsy. Animal studies also showed that seizures are induced byreduction of GABA mneuron function to a critical degree by (1)inhibition of GABA synthesis, (2) blockade of GABA receptors or (3)inhibition of GABA-receptor mediated ionic events. In addition,enhancement of GABA synaptic activity (by direct receptor stimulation orby increasing GABA levels in the synapase) has a potent and widespectrum anticonvulsant effect. These findings foreshadowed that anenhanced and sustained GABA brain delivery or a brain-specific deliveryin a sustained manner of a good GABA-agonist would be efficacious indifferent forms of epilepsy. It is well known that GABA itself, whenadministered systemically, does not penetrate the normal blood-brainbarrier to any significant extent. Among the potential sites at whichdrugs may act to influence GABA-mediated synaptic function, the firsttarget is to effect the BBB transfer of GABA via redox delivery system.The second main target is to effect the catabolism of GABA. Thisinvention, accordingly, specifically provides for the efficaciousdelivery of the GABA-T inhibitors, γ-vinyl and γ-acetylene-GABA, but thedelivery of vaproic acid, specifically to the brain and withoutrequiring high circulating blood levels, is also envisaged. In order toachieve the required activity, sodium valproate must have a relativelyhigh, 50-100 μg/ml, level in the blood. The value of valproic acid iswell established in most types of epilepsy. It is evident that valproicacid produces significant increases in both brain and synaptosomal GABAconcentrations. Valproic acid itself undergoes extensive metabolism.

In capsule summary, the present invention provides for the significantlyimproved treatment of epilepsy, and concomitant reduction in toxicity ofa number of antiepileptic drug species currently in use. And madeavailable to the brain is a variety of important compounds, such as GABAand a wealth of GABA-ergic agents.

Processes similar to those described hereinabove can be shown for thepreparation of the other compounds of this invention. The acylationsteps which introduce hydroxyl protecting groups are of course onlyneeded when there are hydroxyl groups which it is desired to protect.Moreover, carbonate rather than acyl protecting groups could beintroduced instead, as already discused hereinabove. Also, the order ofsteps may be altered; quaternization, followed by reduction, need notalways constitute the final two steps but may be carried out earlier inthe reaction sequence. Yet other reaction schemes, reactants, solvents,reaction conditions, etc. (e.g. using an anhydride rather than an acylhalide for the acylation step, or preparing a different acyl derivativee.g. the acetyl rather than the pivalyl derivative) will be readilyapparent to those skilled in the art. Also, insofar as concerns thequaternary compounds, when an anion different from the one obtained isdesired, the anion in the quaternary salt may be subjected to anionexchange via an anion exchange resin or, more conveniently, by use ofthe method of Kaminski et al, Tetrahedron, Vol. 34, pp. 2857-2859(1978). According to the Kaminski et al method, a methanolic solution ofan HX acid will react with a quaternary ammonium halide to produce themethyl halide and the corresponding quaternary.X salt. Moreover, themanner in which the ultimate compound is prepared should be tailored tothe presence of any other reactive groups in the molecule. For example,when the parent drug contains an --OH or --NH₂ group to be derivatizedas well as carboxy functions, such COOH functions will typically beesterified, e.g. converted to the corresponding ethyl ester, orotherwise suitably protected, usually prior to formation of thequaternary compound. Thus, a wide variety of synthetic approaches can beutilized, depending on the desired structure of the final product. Andcompounds containing more than one category of reactive functionalgroups may be derivatized in a variety of ways; for example, a compoundcontaining reactive hydroxyl and carboxyl groups may have the hydroxylgroup(s) protected and the carboxyl group(s) linked to the carrier, orthe hydroxyl(s) may be linked to the carrier and the carboxyl(s)protected.

Various illustrative synthetic schemes as applied to specific centrallyacting drugs in accord with this invention are set forth below in thesection entitled "Illustrative Synthetic Methods". While the sequence ofreaction steps can be varied in many cases, in general, the final step(except in the case of optional salt formation or possibly in the caseof radiolabeling) will be reduction of a quaternary compound of formula(II) to the corresponding dihydro compound of formula (I). The reductionis usually conducted at a temperature from about -10° C. to roomtemperature, for a period of time from about 10 minutes to 2 hours,conveniently at atmospheric pressure. Typically, a large excess ofreducing agent is employed, e.g., a 1:5 molar ratio of reducing agent tostarting [D--QC]⁺ compound. The process is conducted in the presence ofa suitable reducing agent, preferably an alkali metal dithionite such assodium dithionite or an alkali metal borohydride such as sodiumborohydride or lithium aluminum borohydride, in a suitable solvent.Sodium dithionite reduction is conveniently carried out in an aqueoussolution; the dihydro product [D-DHC] is usually insoluble in water andthus can be readily separated from the reaction medium. In the case ofsodium borohydride reduction, an organic reaction medium is employed,e.g., a lower alkanol such as methanol, an aqueous alkanol or otherprotic solvent.

In a presently preferred embodiment of the present invention, thecentrally acting drug of which D is the residue is dopamine or L-DOPA ora protected counterpart thereof, and the instant redox system is thusdesigned to elicit a sustained and brainspecific dopaminergic (e.g.anti-Parkinsonism or anti-hyperprolactinemia) response in the animal towhich the formula (I) derivative is administered. In an analogousfashion, the instant redox carrier system I→II in which D is the residueof any other centrally acting drug as defined herein is designed toelicit the kind of pharmacological response which would be obtained bydelivery of the drug itself to the brain, i.e., when the centrallyacting parent drug is an antitumor/anticancer agent, the instant redoxsystem is employed to elicit an antitumor/anticancer response; when theparent drug is a sympathetic stimulant, the instant redox system is usedto elicit a sympathetic stimulant or amphetamine-like response; when theparent drug is an anticonvulsant compound, the instant redox system isused to elicit an anticonvulsant response; when the parent drug is atranquilizer, the instant system is used to elicit a tranquilizingresponse; when the parent drug is an antidepressant, the instant systemis used to elicit an antidepressant response; and so forth.

Suitable nontoxic pharmaceutically acceptable carriers for use with thetopic compounds [D--DHC], e.g., those less toxic than the target drugspecies themselves, will be apparent to those skilled in this art.Compare, for example, Remington's Pharmaceutical Sciences, 4th Edition(1970). Obviously, the choice of suitable carriers will depend upon theexact nature of the particular dosage form selected, as well as upon theidentity of the active drug species [D] and the compound to beadministered. The therapeutic dosage ranges for administration of thecompounds according to this invention will generally be the same as, orless than, those which would characteristically be used in this art foradministration of the known drug species [D], per se. Naturally, suchtherapeutic dosage ranges will vary with the size of the patient, thecondition for which the [D--DHC] compound is administered, theparticular dosage form employed, and the like. The quantity of givendosage form needed to deliver the desired dose of [D] will of coursedepend upon the concentration of [D--DHC] in any given pharmaceuticalcomposition/dosage form thereof. Obviously, in the case of diagnosticagents, the dosage of formula (I) compound used will be a quantitysufficient to deliver to the target body area a quantity sufficient todeliver an amount of radioisotope, stable isotope or the like which canbe effectively detected by radioimaging or other detection means. Theamount of radioisotope, stable isotope or the like present in the dosageform will be within or below the ranges conventionally used fordiagnostic purposes.

The ability of the topic compounds to cross the BBB and to be "lockedinto " the brain allows administration of the drug in a site-specificmanner. A combination of the present dihydropyridine⃡pyridinium saltredox system with a sustained release system will further enhance thissite-specificity. Thus, a preferred embodiment of the inventioncomprises formulating the [D--DHC] compound or the salt of the [D--DHC]compound utilizing a sustained release carrier system and/or route ofadministration capable of slowly releasing the chemical, e.g. sustainedrelease tablets and capsules for oral administration; subcutaneousinjection, or implantation of drugs in solid pellet form (for example,distributed in a biodegradable polymer); intramuscular injection of thecompound in solution in oil or suspended in a repository vehicle; atransdermal delivery device or form such as an ointment to be appliedlocally to the desired site (when the drug is susceptible of deliverythrough the skin), slow intravenous infusion and the like. The rate ofrelease of compound from the sustained release system should becomparable to the rate of in vivo oxidation of the dihydro form of theredox system in order to achieve the greatest degree of enhancement ofspecificity.

In applicant's copending application Ser. No. 632,314, filed July 19,1984 (itself a continuation-in-part of applicant's earlier Ser. Nos.379,316, 461,543, 475,493 and 516,382), the concept of applicant's redoxcarrier system was expanded to provide novel carrier-containingchelating agents, precursors thereto and radiopharmaceuticals derivedtherefrom, utilizing the dihydropyridine⃡pyridinium salt type carriersdisclosed herein and in the four earlier applications. The presentapplication discloses several specific groups of carrier moieties onlygenerically disclosed in its parent applications. The teachings of Ser.No. 632,314, which is incorporated by reference herein in its entiretyand relied upon, can be readily combined with the teachings of thepresent application to expand the classes of chelating agents,precursors and radiopharmaceuticals defined therein to specificallyinclude the new dihydropyridine⃡pyridinium salt redox carriers disclosedin the present application.

ILLUSTRATIVE SYNTHETIC METHODS I. Methods for Derivatizing --NH₂ or--NH-- Functions in Drugs Method A

The drug is reacted with nicotinoyl chloride, with nicotinic anhydride,or with nicotinic acid in the presence of a suitable coupling agent suchas dicyclohexylcarbodiimide, in an appropriate organic solvent, toafford the corresponding nicotinamide. The nicotinamide is thenquaternized, typically by treatment with methyl iodide in a suitableorganic solvent, to afford the quaternary derivative of formula (II),which is then reduced by treatment with sodium dithionite or sodiumborohydride as generally described hereinabove to afford the desiredcompound of formula (I). The representative drugs depicted below may bederivatized in this manner to the corresponding compounds of formulas(II) and (I). Compounds such as bupropion, difluamine, propranolol,ethyl β-carboline-3-carboxylate, prizidilol, pseudoephedrine,5-amidino-2-(5-amidino-2-benzofuranyl)indole,4',6-diimidazolino-2-phenylbenzo(b)thiophene,2-guanidino-4,5-di-n-propyloxazole, 2-guanidino-4,5-diphenyloxazole,glucosamine, 6-amino-6-deoxy-D-glucose, somatostatin, vasopressin and6[[(hydroxyimino)phenyl]methyl]-1-[(methylethyl)sulfonyl-1H-benzimidazol-2-aminemay be similarly derivatized.

The foregoing procedure may be repeated using picolinic acid or its acidchloride or anhydride, or isonicotinic acid or its acid chloride oranhydride, in place of nicotinic acid or its acid chloride or anhydride,respectively, to convert drugs such as those specifically mentioned forderivatizing by this method to the corresponding picolinamides andisonicotinamides and then to the corresponding compounds of formulas(II) and (I).

Alternatively, the drug may be reacted with an activated ester ofnicotinic acid, picolinic acid or isonicotinic acid, e.g. a succinimidylester such as ##STR53## and the procedure described above repeated toafford the identical products. As yet another alternative, the activatedester, e.g. the succinimidyl ester depicted above, may be quaternized(e.g. by treatment with methyl iodide) and the quaternized activatedester then reacted with the drug. The quaternary compound of formula(II) thus obtained may then be reduced as described in the firstparagraph of this method to give the corresponding compound of formula(I).

      Starting Material [DQC].sup.+      * [DDHC]      ##STR54##      ##STR55##      ##STR56##      ##STR57##      ##STR58##      ##STR59##      ##STR60##      ##STR61##      ##STR62##      ##STR63##      ##STR64##      ##STR65##      ##STR66##      ##STR67##      ##STR68##      ##STR69##      ##STR70##      ##STR71##      ##STR72##      ##STR73##      ##STR74##      ##STR75##      ##STR76##      ##STR77##      ##STR78##      ##STR79##      ##STR80##      ##STR81##      ##STR82##      ##STR83##      ##STR84##      ##STR85##      ##STR86##      ##STR87##      ##STR88##      ##STR89##      ##STR90##      ##STR91##      ##STR92##      ##STR93##      ##STR94##      ##STR95##      ##STR96##      ##STR97##      ##STR98##      ##STR99##      ##STR100##      ##STR101##      ##STR102##      ##STR103##      ##STR104##      ##STR105##      ##STR106##      ##STR107##      ##STR108##      ##STR109##      ##STR110##      ##STR111##      ##STR112##      ##STR113##      ##STR114##      ##STR115##      ##STR116##      ##STR117##      ##STR118##      ##STR119##      ##STR120##      ##STR121##      ##STR122##      ##STR123##      ##STR124##      ##STR125##      ##STR126##      ##STR127##      ##STR128##      ##STR129##      ##STR130##      ##STR131##      ##STR132##      ##STR133##      ##STR134##      ##STR135##      ##STR136##      ##STR137##      ##STR138##      ##STR139##      ##STR140##      ##STR141##      ##STR142##      ##STR143##      ##STR144##      ##STR145##      ##STR146##      ##STR147##      ##STR148##      ##STR149##      ##STR150##      ##STR151##      ##STR152##      ##STR153##      ##STR154##      ##STR155##      ##STR156##      ##STR157##      ##STR158##      ##STR159##      ##STR160##      ##STR161##      ##STR162##      ##STR163##      ##STR164##      ##STR165##      ##STR166##      ##STR167##      ##STR168##      ##STR169##      ##STR170##      ##STR171##      ##STR172##      ##STR173##      ##STR174##      ##STR175##      ##STR176##      ##STR177##      ##STR178##      ##STR179##      ##STR180##      ##STR181##      ##STR182##      ##STR183##      ##STR184##      ##STR185##      ##STR186##      ##STR187##      ##STR188##      ##STR189##      ##STR190##      ##STR191##      ##STR192##      ##STR193##      ##STR194##      ##STR195##      ##STR196##      ##STR197##      ##STR198##      ##STR199##      ##STR200##      ##STR201##      ##STR202##      ##STR203##      ##STR204##      ##STR205##      ##STR206##      ##STR207##      ##STR208##      ##STR209##      ##STR210##      ##STR211##      ##STR212##      ##STR213##      ##STR214##      ##STR215##     *cation only depicted in this column throughout Illustrative Synthetic     Methods

Method B

This is a variation of Method A used when the drug contains at least one--COOH function which is to be protected.

The drug is first converted to the corresponding ethyl or t-butyl esterby conventional esterification techniques. That ester is then used asthe starting material and Method A is repeated.

Obviously, other esters may be similarly prepared in the first step byuse of other esterifying agents.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Omegaamino acids other than GABA, other natural amino acids such as glycine,tyrosine, aspartic acid and glutamic acid, small peptides (2-20 aminoacids, e.g. met⁵ -enkephalin and leu⁵ -enkephalin), ceforanide,furosemide and the like may be similarly derivatized.

The picolinamide and isonicotinamide quaternary and dihydro derivativesof the drugs specifically mentioned for derivatizing according to thismethod may be similarly prepared. See Method A.

      Starting Material [DQC].sup.+ [DDHC]      ##STR216##      ##STR217##      ##STR218##      ##STR219##      ##STR220##      ##STR221##      ##STR222##      ##STR223##      ##STR224##      ##STR225##      ##STR226##      ##STR227##      ##STR228##      ##STR229##      ##STR230##      ##STR231##      ##STR232##      ##STR233##      ##STR234##      ##STR235##      ##STR236##      ##STR237##      ##STR238##      ##STR239##      ##STR240##      ##STR241##      ##STR242##      ##STR243##      ##STR244##      ##STR245##      ##STR246##      ##STR247##      ##STR248##      ##STR249##      ##STR250##      ##STR251##      ##STR252##      ##STR253##      ##STR254##      ##STR255##      ##STR256##      ##STR257##

Method C

This is a variation of Method A used when the drug contains one or moreOH functions which are to be protected.

The drug is first reacted with excess trimethylacetyl chloride toconvert the hydroxy group(s) to pivalyloxy group(s). (This process isgenerally conducted in the presence of a base; however, strongly acidconditions are used if an amine function is present.) That protectedderivative is then used as the starting material and subjected to MethodA. Alternatively, the first two steps may be reversed, i.e. the drug maybe first converted to the nicotinamide, which may then be reacted withtrimethylacetyl chloride to form the protected nicotinamide.

Various other hydroxy protecting groups may be introduced in similarfashion.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Thecorresponding picolinamide and isonicotinamide quaternary and dihydroderivatives may be similarly prepared. See Method A. Moreover, drugssuch as atenolol, metoprolol, pentostatin (2'-deoxycoformycin),glucosamine, 6-amino-6-deoxy-D-glucose and pseudoephedrine may besimilarly derivatized.

      Starting Material [DQC].sup.+ [DDHC]      ##STR258##      ##STR259##      ##STR260##      ##STR261##      ##STR262##      ##STR263##      ##STR264##      ##STR265##      ##STR266##      ##STR267##      ##STR268##      ##STR269##      ##STR270##      ##STR271##      ##STR272##      ##STR273##      ##STR274##      ##STR275##      ##STR276##      ##STR277##      ##STR278##

Method D

This variation of Method A can be used when the drug contains one ormore OH and COOH functions which are to be protected. The protectinggroups, typically the ethyl or t-butyl ester and pivalyloxy groups, areintroduced as described in Methods B and C, in the sequence consideredmost convenient. Obviously, other protecting groups can be introducedinstead. The amine function is derivatized according to Method A.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Thecorresponding picolinamide and isonicotinamide quaternary and dihydroderivatives may be similarly prepared. See Method A.

    __________________________________________________________________________    Starting Material                                                                            [DQC].sup.+             [DDHC]                                 __________________________________________________________________________     ##STR279##                                                                                   ##STR280##                                                                                            ##STR281##                             ##STR282##                                                                                   ##STR283##                                                                                            ##STR284##                            __________________________________________________________________________

Method E

This method is of particular use when the --NH-- function is part of anamide or imide or a very low pKa primary or secondary amine.

The drug is first reacted with an aldehyde [e.g. formaldehyde,benzaldehyde, acetaldehyde or chloral (Cl₃ CCHO)]; for example, in thecase of formaldehyde or chloral, one converts the --NH-- function to a##STR285## function, respectively, and thus forms a suitable bridginggroup. The resultant compound can then be derivatized in the same manneras any drug containing a reactive --OH group; for example, it is thenreacted with nicotinic acid in the presence of a suitable couplingagent, or with nicotinoyl chloride or nicotinic anhydride, to form thecorresonding nicotinic acid ester of the partial formula ##STR286##respectively. The resultant intermediate is then quaternized and reducedas in Method A. The alternative process utilizing an activated ester orquaternary derivative thereof which is described in Method A may beutilized here as well.

The representative starting drugs depicted below may be derivatized inthis manner to the corresponding compounds of formulas (II) and (I).Drugs such as minocycline, doxycycline, oxytetracycline, tetracycline,methacycline, atenolol, sulfadiazine, dactinomycin, mitomycin,methylphenidate, ethyl β-carboline 3-carboxylate, nifedipine,3-deazaguanine, 6-mercaptopurine, cyclophosphamide and progabide may besimilarly derivatized.

The foregoing procedure may be repeated using picolinic acid or its acidchloride or anhydride or activated ester, or isonicotinic acid or itsacid chloride or anhydride or activated ester, in place of nicotinicacid or its acid chloride or anhydride, or activated ester,respectively, to convert drugs such as those specifically mentioned forderivatizing according to this method to the corresponding picolinicacid esters and isonicotinic acid esters and then to the correspondingcompounds of formulas (II) and (I).

As yet another alternative, the intermediate compound containing the##STR287## group or the like may be reacted with thionyl chloride toafford the corresponding compound containing a ##STR288## or similargroup. That derivative may then be reacted with a metallic salt(especially a silver or thallous salt) of nicotinic acid or the like(formed, e.g. by reacting nicotinic acid or the like with fresh silverhydroxide or oxide or with thallous ethoxide). The resultant nicotinicacid ester of the partial formula ##STR289## or like derivative is thenquaternized and subsequently reduced as in Method A.

      Starting Material [DQC].sup.+ [DDHC]      ##STR290##      ##STR291##      ##STR292##      ##STR293##      ##STR294##      ##STR295##      ##STR296##      ##STR297##      ##STR298##      ##STR299##      ##STR300##      ##STR301##      ##STR302##      ##STR303##      ##STR304##      ##STR305##      ##STR306##      ##STR307##      ##STR308##      ##STR309##      ##STR310##      ##STR311##      ##STR312##      ##STR313##      ##STR314##      ##STR315##      ##STR316##      ##STR317##      ##STR318##      ##STR319##      ##STR320##      ##STR321##      ##STR322##      ##STR323##      ##STR324##      ##STR325##      ##STR326##      ##STR327##      ##STR328##      ##STR329##      ##STR330##      ##STR331##      ##STR332##      ##STR333##      ##STR334##      ##STR335##      ##STR336##      ##STR337##      ##STR338##      ##STR339##      ##STR340##      ##STR341##      ##STR342##      ##STR343##      ##STR344##      ##STR345##      ##STR346##      ##STR347##      ##STR348##      ##STR349##      ##STR350##      ##STR351##      ##STR352##      ##STR353##      ##STR354##      ##STR355##      ##STR356##      ##STR357##      ##STR358##      ##STR359##      ##STR360##      ##STR361##      ##STR362##      ##STR363##      ##STR364##      ##STR365##      ##STR366##      ##STR367##      ##STR368##      ##STR369##      ##STR370##      ##STR371##      ##STR372##      ##STR373##      ##STR374##      ##STR375##      ##STR376##      ##STR377##      ##STR378##      ##STR379##      ##STR380##      ##STR381##      ##STR382##

Method F

This method is a variation of Method E which can be used when the --NH--function is part of an amide or imide or low pKa primary or secondaryamine and the drug contains one or more --COOH functions which is/are tobe protected. Typically, the carboxyl group or groups is/are firstconverted to the corresponding pivaloyloxymethyl ester by knownesterification techniques. Obviously, other esters may be similarlyprepared. The ester is then used as the starting material and Method Eis repeated.

The representative starting drugs depicted below may be derivatized inthis manner to the corresponding compounds of formulas (II) and (I).Drugs such as carbenicillin, phenoxymethylpenicillin, methicillin,nafcillin, ticarcillin, dicloxacillin, cefazolin, cefoxitin, moxalactam,aminopterin, furosemide, and 5-methyltetrahydrohomofolic acid may besimilarly derivatized.

The alternative procedures described in Method E may be used in Method Falso.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR383##      ##STR384##      ##STR385##      ##STR386##      ##STR387##      ##STR388##      ##STR389##      ##STR390##      ##STR391##      ##STR392##      ##STR393##      ##STR394##      ##STR395##      ##STR396##      ##STR397##      ##STR398##

Method G

This is a variation of Method E used when the drug also contains one ormore hydroxy functions which are to be protected. Typically, the drug isfirst reacted with excess trimethylacetyl chloride to convert thehydroxy group(s) to pivalyloxy group(s). That protected derivative isthen used as the starting material and subjected to Method E.

Other hydroxy protecting groups may be introduced in similar fashion.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I).

The alternative procedures described in Method E may be used in Method Galso.

    __________________________________________________________________________    STARTING MATERIAL [DQC].sup.+           [DDHC]                                __________________________________________________________________________     ##STR399##                                                                                      ##STR400##                                                                                          ##STR401##                            ##STR402##                                                                                      ##STR403##                                                                                          ##STR404##                            ##STR405##                                                                                      ##STR406##                                                                                          ##STR407##                           __________________________________________________________________________

Method H

Method A is followed, except that in the first step, the drug is reactedwith 3-quinolinecarboxylic acid or its acid chloride or anhydride oractivated ester instead of nicotinic acid or its acid chloride oranhydride or activated ester.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I), as maythe remaining drugs mentioned with Method A.

Similarly, Method H may be combined with Methods B, C, D, E, F or G toafford the corresponding derivatives, e.g., of the drugs listed withthose methods.

The foregoing procedure can be repeated using 4-isoquinolinecarboxylicacid or its acid chloride or anhydride or activated ester in place of3-quinolinecarboxylic acid or its acid chloride or anhydride oractivated ester to convert drugs such as those mentioned with Methods A,B, C, D, E, F or G to the corresponding derivatives.

The general procedures described above may be utilized to provide the1,2-dihydro derivatives as well as the depicted 1,4-dihydros.

      Starting Material [DQC].sup.+ [DDHC]      ##STR408##      ##STR409##      ##STR410##      ##STR411##      ##STR412##      ##STR413##      ##STR414##      ##STR415##      ##STR416##      ##STR417##      ##STR418##      ##STR419##      ##STR420##      ##STR421##      ##STR422##      ##STR423##      ##STR424##      ##STR425##      ##STR426##      ##STR427##      ##STR428##      ##STR429##      ##STR430##      ##STR431##      ##STR432##      ##STR433##      ##STR434##      ##STR435##      ##STR436##      ##STR437##      ##STR438##      ##STR439##      ##STR440##      ##STR441##      ##STR442##      ##STR443##

Method I

Method A is followed, except that in the first step, a reactant of theformula ##STR444## is used in place of nicotinic acid. (That startingmaterial may be prepared by reacting nicotinic anhydride, nicotinoylchloride or nicotinic acid with glycolic acid.)

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I), as maythe remaining drugs mentioned with Method A.

Similarly, Method I may be combined with Methods B, C, D, E, F or G toafford the corresponding derivatives, e.g. of the drugs mentioned withthose methods.

The foregoing procedure can be repeated using picolinic acid or its acidchloride or anhydride, or isonicotinic acid or its acid chloride oranhydride, in place of nicotinic acid or its acid chloride or anhydride,respectively, in the preparation of the reactant depicted above. Thisvariation affords a reactant of the formula ##STR445## which can then beused in place of nicotinic acid to prepare derivatives of drugs such asthose mentioned with Methods A, B, C, D, E, F or G.

      Starting Material [DQC].sup.+ [DDHC]      ##STR446##      ##STR447##      ##STR448##      ##STR449##      ##STR450##      ##STR451##      ##STR452##      ##STR453##      ##STR454##      ##STR455##      ##STR456##      ##STR457##      ##STR458##      ##STR459##      ##STR460##      ##STR461##      ##STR462##      ##STR463##      ##STR464##      ##STR465##      ##STR466##

Method J

Method A is followed, except that in the first step, a reactant of theformula ##STR467## wherein n=1-3, preferably 2, is used in place ofnicotinic acid. (That starting material may be prepared fromnicotinamide, e.g. when n=2, by reacting 3-liodopropionic acid withnicotinamide.) The quaternary salt of formula (II) thus obtained maythen be reduced as described in Method A.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method A.

Similarly, Mehtod J may be combined with Methods B, C, D, E, F or G toafford the corresponding derivatives, e.g. of the drugs mentioned withthose methods.

The foregoing procedure can be repeated using picolinamide orisonicotinamide in place of nicotinamide in the preparation of thestarting material. This variation affords a reactant of the formula##STR468## which can then be used in place of nicotinic acid in theprocedure of this method, to afford the corresponding derivatives, e.g.of the drugs mentioned with Methods A, B, C, D, E, F or G.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR469##      ##STR470##      ##STR471##      ##STR472##      ##STR473##      ##STR474##      ##STR475##      ##STR476##      ##STR477##      ##STR478##      ##STR479##      ##STR480##      ##STR481##      ##STR482##      ##STR483##

II. Methods for Derivatizing --OH and --SH Functions in Drugs Method K

The drug is reacted with nicotinoyl chloride, with nicotinic anhydride,or with nicotinic acid in the presence of a suitable coupling agent suchas dicyclohexylcarbodiimide, in an appropriate organic solvent, toafford the corresponding nicotinate. The nicotinate is then quaternizedand subsequently reduced as described above in Method A. When the drugcontains more than one reactive hydroxyl or thiol function, reactionconditions may be varied so that more than one hydroxyl or thiolfunction will be converted to nicotinate groupings. The alternativeprocess utilizing an activated ester or quaternary derivative thereofwhich is described in Method A may be utilized here as well.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I).2-Deoxy-D-glucose, 2-deoxy-2-fluoro-D-mannose, bisdihydroxyvinyluridine(BDVU), meptazinol, cyclazocine, phenazocine, metopon, myfadol,thioguanine, naltrexone, alazocine, oxilorphan, nalmexone and estriolmay be similarly derivatized.

The foregoing procedure may be repeated using picolinic acid or its acidchloride or anhydride or activated ester, or isonicotinic acid or itsacid chloride or anhydride or activated ester, in place of nicotinicacid or its acid chloride or anhydride or activated ester, respectively,to convert drugs such as those specifically mentioned for derivatizingby this method to the corresponding picolinic acid esters orisonicotinic acid esters and then to the corresponding compounds offormulas (II) and (I).

      Starting Material [DQC].sup.+ [DDHC]      ##STR484##      ##STR485##      ##STR486##      ##STR487##      ##STR488##      ##STR489##      ##STR490##      ##STR491##      ##STR492##      ##STR493##      ##STR494##      ##STR495##      ##STR496##      ##STR497##      ##STR498##      ##STR499##      ##STR500##      ##STR501##      ##STR502##      ##STR503##      ##STR504##      ##STR505##      ##STR506##      ##STR507##      ##STR508##      ##STR509##      ##STR510##      ##STR511##      ##STR512##      ##STR513##      ##STR514##      ##STR515##      ##STR516##      ##STR517##      ##STR518##      ##STR519##      ##STR520##      ##STR521##      ##STR522##      ##STR523##      ##STR524##      ##STR525##      ##STR526##      ##STR527##      ##STR528##      ##STR529##      ##STR530##      ##STR531##      ##STR532##      ##STR533##      ##STR534##      ##STR535##      ##STR536##      ##STR537##      ##STR538##      ##STR539##      ##STR540##      ##STR541##      ##STR542##      ##STR543##      ##STR544##      ##STR545##      ##STR546##      ##STR547##      ##STR548##      ##STR549##      ##STR550##      ##STR551##      ##STR552##      ##STR553##      ##STR554##      ##STR555##      ##STR556##      ##STR557##      ##STR558##      ##STR559##      ##STR560##      ##STR561##      ##STR562##      ##STR563##      ##STR564##      ##STR565##      ##STR566##      ##STR567##      ##STR568##      ##STR569##      ##STR570##      ##STR571##      ##STR572##      ##STR573##      ##STR574##      ##STR575##      ##STR576##      ##STR577##      ##STR578##      ##STR579##      ##STR580##      ##STR581##      ##STR582##      ##STR583##      ##STR584##      ##STR585##      ##STR586##      ##STR587##      ##STR588##

      Starting Material [DQC].sup.+ [DDHC]      ##STR589##      ##STR590##      ##STR591##      ##STR592##      ##STR593##      ##STR594##      ##STR595##      ##STR596##      ##STR597##      ##STR598##      ##STR599##      ##STR600##      ##STR601##      ##STR602##      ##STR603##      ##STR604##      ##STR605##      ##STR606##      ##STR607##      ##STR608##      ##STR609##      ##STR610##      ##STR611##      ##STR612##      ##STR613##      ##STR614##      ##STR615##      ##STR616##      ##STR617##      ##STR618##      ##STR619##      ##STR620##      ##STR621##      ##STR622##      ##STR623##      ##STR624##      ##STR625##      ##STR626##      ##STR627##      ##STR628##      ##STR629##      ##STR630##      ##STR631##      ##STR632##      ##STR633##      ##STR634##      ##STR635##      ##STR636##      ##STR637##      ##STR638##      ##STR639##      ##STR640##      ##STR641##      ##STR642##      ##STR643##      ##STR644##      ##STR645##      ##STR646##      ##STR647##      ##STR648##       This compound can be selectively  hydrolyzed by known methods to  the     corresponding 17-monoester,  which can be reduced to give the  preferred     17-monoester of formula (I).      ##STR649##      ##STR650##      ##STR651##      ##STR652##      ##STR653##      ##STR654##      ##STR655##      ##STR656##      ##STR657##      ##STR658##      ##STR659##      ##STR660##      ##STR661##      ##STR662##      ##STR663##      ##STR664##      ##STR665##      ##STR666##      ##STR667##      ##STR668##      ##STR669##      ##STR670##      ##STR671##      ##STR672##      ##STR673##      ##STR674##      ##STR675##      ##STR676##      ##STR677##      ##STR678##      ##STR679##      ##STR680##      ##STR681##      ##STR682##      ##STR683##      ##STR684##      ##STR685##      ##STR686##      ##STR687##      ##STR688##      ##STR689##      ##STR690##      ##STR691##

      Starting Material [DQC].sup.+ [DDHC]      ##STR692##      ##STR693##      ##STR694##      ##STR695##      ##STR696##      ##STR697##      ##STR698##      ##STR699##      ##STR700##      ##STR701##      ##STR702##      ##STR703##      ##STR704##      ##STR705##      ##STR706##      ##STR707##      ##STR708##      ##STR709##      .sup.      ##STR710##      ##STR711##      ##STR712##      ##STR713##      ##STR714##      ##STR715##      ##STR716##      ##STR717##      ##STR718##      ##STR719##      ##STR720##      ##STR721##      ##STR722##      ##STR723##      ##STR724##      ##STR725##      ##STR726##      ##STR727##      ##STR728##      ##STR729##      ##STR730##      ##STR731##      ##STR732##      ##STR733##      ##STR734##      ##STR735##      ##STR736##      ##STR737##      ##STR738##      ##STR739##      ##STR740##      ##STR741##      ##STR742##      ##STR743##      ##STR744##      ##STR745##      ##STR746##      ##STR747##      ##STR748##      ##STR749##      ##STR750##      ##STR751##      ##STR752##      ##STR753##      ##STR754##      ##STR755##      ##STR756##      ##STR757##      ##STR758##      ##STR759##      ##STR760##      ##STR761##      ##STR762##      ##STR763##      ##STR764##      ##STR765##      ##STR766##      ##STR767##      ##STR768##      ##STR769##      ##STR770##      ##STR771##      ##STR772##      ##STR773##      ##STR774##      ##STR775##      ##STR776##      ##STR777##      ##STR778##      ##STR779##      ##STR780##      ##STR781##      ##STR782##      ##STR783##      ##STR784##      ##STR785##      ##STR786##      ##STR787##      ##STR788##      ##STR789##      ##STR790##      ##STR791##      ##STR792##      ##STR793##      ##STR794##      ##STR795##      ##STR796##      ##STR797##      ##STR798##      ##STR799##      ##STR800##      ##STR801##      ##STR802##

      Starting Material [DQC].sup.+ [DDHC]      ##STR803##      ##STR804##      ##STR805##      ##STR806##      ##STR807##      ##STR808##      ##STR809##      ##STR810##      ##STR811##      ##STR812##      ##STR813##      ##STR814##      ##STR815##      ##STR816##      ##STR817##      ##STR818##      ##STR819##      ##STR820##      ##STR821##      ##STR822##      ##STR823##      ##STR824##      ##STR825##      ##STR826##      ##STR827##      ##STR828##      ##STR829##      ##STR830##      ##STR831##      ##STR832##      ##STR833##      ##STR834##      ##STR835##      ##STR836##      ##STR837##      ##STR838##      ##STR839##      ##STR840##      ##STR841##      ##STR842##      ##STR843##      ##STR844##      ##STR845##      ##STR846##      ##STR847##      ##STR848##      ##STR849##      ##STR850##      ##STR851##      ##STR852##      ##STR853##      ##STR854##      ##STR855##      ##STR856##      ##STR857##      ##STR858##      ##STR859##      ##STR860##      ##STR861##      ##STR862##      ##STR863##      ##STR864##      ##STR865##      ##STR866##      ##STR867##      ##STR868##      ##STR869##      ##STR870##      ##STR871##      ##STR872##      ##STR873##      ##STR874##      ##STR875##      ##STR876##      ##STR877##      ##STR878##      ##STR879##      ##STR880##      ##STR881##      ##STR882##      ##STR883##      ##STR884##      ##STR885##      ##STR886##      ##STR887##      ##STR888##      ##STR889##      ##STR890##      ##STR891##      ##STR892##      ##STR893##      ##STR894##      ##STR895##      ##STR896##      ##STR897##      ##STR898##      ##STR899##      ##STR900##      ##STR901##      ##STR902##      ##STR903##      ##STR904##      ##STR905##      ##STR906##      ##STR907##      ##STR908##      ##STR909##      ##STR910##      ##STR911##      ##STR912##      ##STR913##      ##STR914##      ##STR915##      ##STR916##      ##STR917##

Method K'

This is an alternate process for derivatizing drugs containing secondaryor tertiary hydroxyl functional groups. According to this process, thedrug is reacted with chloral or other aldehyde capable of forming ahemiacetal therewith. In the case of chloral, this converts the --OHfunction(s) to ##STR918## groupings.

The --OH function(s) of the resultant hemiacetal can then be derivatizedby any of the methods for derivatizing --OH groups disclosedhereinabove, e.g. by reaction with nicotinic acid or its acid chlorideor anhydride as described in Method K.

This process is of particular value when the --OH group(s) in the drugis/are sterically hindered and/or when it is desired to alter the rateof release of the drug from that obtained when the carrier is hookeddirectly to the drug's hydroxy function(s).

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Otherdrugs containing secondary or tertiary --OH groups which are disclosedherein, e.g. in connection with Method K, may be similarly derivatized.This method is of special interest for derivatizing steroids containingsecondary or tertiary 17 β-hydroxy substituents, especially steroid sexhormones, and most especially such hormones bearing a bulky 17α-substituent such as a 17 α-ethynyl grouping.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR919##      ##STR920##      ##STR921##      ##STR922##      ##STR923##      ##STR924##      ##STR925##      ##STR926##      ##STR927##      ##STR928##      ##STR929##      ##STR930##      ##STR931##      ##STR932##      ##STR933##      ##STR934##      ##STR935##      ##STR936##

Method L

This variation of Method K can be used when the drug contains an aminogroup which needs to be protected. Generally, the amino group isprotected prior to any reaction of the hydroxyl function; typically, abenzyloxycarbonyl group is introduced in conventional manner to protectthe amino function and then the process described in Method K isfollowed. Removal of the protecting group, also in conventional manner,takes place after protection is no longer needed, be it at the end ofthe synthetic pathway or earlier. Generally, the protecting group isremoved before formation of the formula (II) quaternary. Occasionally,an amino protecting group will be utilized which need not be removed,for example, in the case of trifluoroacetyldoxorubicin below.

The representative N- protected drugs depicted below may be derivatizedin this manner to the corresponding compounds of formulas (II) and (I).Drugs such as norepinephrine, epinephrine, glucosamine,6-amino-6-deoxy-D-glucose and pseudoephedrine may be similarlyderivatized.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR937##      ##STR938##      ##STR939##      ##STR940##      ##STR941##      ##STR942##      ##STR943##      ##STR944##      ##STR945##      ##STR946##      ##STR947##      ##STR948##      ##STR949##      ##STR950##      ##STR951##

Method M

This is a variation of Method K used when the drug contains a --COOHfunction which is to be protected.

The drug is first converted to the corresponding ethyl or t-butyl esterby conventional esterification techniques. That ester is then used asthe starting material and Method K is repeated. The --COOH group may besimilarly converted to other ester groups.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I).Diflunisal, clorazepate and captopril may be similarly derivatized.

The picolinic acid ester and isonicotinic acid ester quaternary anddihydro derivatives of the drugs specifically mentioned for derivatizingaccording to this method may be similarly prepared. See Method K.

      Starting Material [DQC].sup.+ [DDHC]      ##STR952##      ##STR953##      ##STR954##      ##STR955##      ##STR956##      ##STR957##      ##STR958##      ##STR959##      ##STR960##      ##STR961##      ##STR962##      ##STR963##      ##STR964##      ##STR965##      ##STR966##

Method N

Method K is followed, except that a reactant of the formula ##STR967##wherein n=1-3, preferably 2, is used in place of nicotinic acid. Thequaternary salt of formula (II) thus obtained may then be reduced asdescribed in Method A.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I) as maythe remaining drugs listed with Method K.

Similarly, Method N may be combined with Method L or M to afford thecorresponding derivatives, e.g. of the drugs mentioned with thosemethods.

A starting material of the formula set forth immediately above can alsobe substituted for nicotinic acid in Method E, F or G to afford thecorresponding derivatives, e.g of the drugs mentioned with thosemethods.

Method N is of particular use in preparing derivatives of drugs in whichthe hydroxy function is hindered, e.g., biperiden, cycrimine,procyclidine and trihexyphenidyl.

Alternatively, Method N may follow Method K except that it employs areactant of the formula ##STR968## (prepared as described in Method J),to afford derivatives of the drugs indicated with Method K. Thisaltlernative form of Method N may also be combined with Method L or M,to afford the corresponding derivatives of the drugs mentioned withMethod L or M, respectively. Also, these alternative Method N startingmaterials may be substituted for nicotinic acid in Method E, F or G togive the corresponding derivatives of the drugs mentioned with thosemethods.

      Starting Material [DQC].sup.+ [DDHC]      ##STR969##      ##STR970##      ##STR971##      ##STR972##      ##STR973##      ##STR974##      ##STR975##      ##STR976##      ##STR977##      ##STR978##      ##STR979##      ##STR980##      ##STR981##      ##STR982##      ##STR983##      ##STR984##      ##STR985##      ##STR986##      ##STR987##      ##STR988##      ##STR989##      ##STR990##      ##STR991##      ##STR992##      ##STR993##      ##STR994##      ##STR995##      ##STR996##      ##STR997##      ##STR998##      ##STR999##      ##STR1000##      ##STR1001##

Method O

Method K is followed, except that the drug is reacted with3-quinolinecarboxylic acid or its acid chloride or anhydride oractivated ester instead of nicotinic acid or its acid chloride oranhydride or activated ester.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I), as maythe remaining drugs mentioned with Method K.

Similarly, Method O may be combined with Method L or M to afford thecorresponding derivatives, e.g. of the drugs mentioned with thosemethods.

The procedure of Method O may be repeated using 4-isoquinolinecarboxylicacid or its acid chloride or anhydride or activated ester in place of3-quinolinecarboxylic acid or its acid chloride or anhydride oractivated ester, to afford the corresponding derivatives of drugs suchas those indicated with Methods K, L, and M.

3-Quniolinecarboxylic acid or its acid chloride or anhydride oractivated ester or 4-isoquinolinecarboxylic acid or its acid chloride oranhydride or activated ester can also be substituted for nicotinic acidor its acid chloride or anhydride or activated ester in Method E, F orG, to afford the corresponding derivatives, e.g., of the drugs mentionedwith those methods.

The general procedures described above may be utilized to provide the1,2-dihydro derivatives as well as the depicted 1,4-dihydros.

      Starting Material [DQC].sup.+ [DDHC]      ##STR1002##      ##STR1003##      ##STR1004##      ##STR1005##      ##STR1006##      ##STR1007##      ##STR1008##      ##STR1009##      ##STR1010##      ##STR1011##      ##STR1012##      ##STR1013##      ##STR1014##      ##STR1015##      ##STR1016##      ##STR1017##      ##STR1018##      ##STR1019##      ##STR1020##      ##STR1021##      ##STR1022##      ##STR1023##      ##STR1024##      ##STR1025##      ##STR1026##      ##STR1027##      ##STR1028##      ##STR1029##      ##STR1030##      ##STR1031##      ##STR1032##      ##STR1033##      ##STR1034##      ##STR1035##      ##STR1036##      ##STR1037##      ##STR1038##      ##STR1039##

Method P

Method K is followed, except that a reactant of the formula ##STR1040##is used in place of nicotinic acid.

The representative drugs mentioned below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I), as maythe remaining drugs mentioned with Method K.

Similarly, Method P may be combined with Methods L and M to afford thecorresponding derivatives, e.g. of the drugs mentioned with thosemethods.

A starting material of the formula set forth immediately above can alsobe substituted for nicotinic acid in Method E, F or G to afford thecorresponding derivatives, e.g. of the drugs mentioned with thosemethods.

Alternatively, Method P may follow Method K except that it employs areactant of the formula ##STR1041## (prepared as described in Method I),to afford derivatives of the drugs indicated with method K. Thisalternative form of Method P may also be combined with Method L or M, toafford the corresponding derivatives of the drugs mentioned with MethodL or M. also, these alternative Method P starting materials may besubstituted for nicotinic acid in Method E, F or G to give thecorresponding derivatives of the drugs specified wwith those methods.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1042##      ##STR1043##      ##STR1044##      ##STR1045##      ##STR1046##      ##STR1047##      ##STR1048##      ##STR1049##      ##STR1050##      ##STR1051##      ##STR1052##      ##STR1053##      ##STR1054##      ##STR1055##      ##STR1056##      ##STR1057##      ##STR1058##      ##STR1059##      This compound can be subsequently selectively hydrolyzed by known     methods to the corresponding 17-monoester of formula (II), which can be     reduced to the corresponding preferred 17-monoester of formula (I).      ##STR1060##      ##STR1061##      ##STR1062##      ##STR1063##      ##STR1064##      ##STR1065##

III. Methods for Derivatizing --COOH Functions in Drugs Method Q

Nicotinic acid or an activated ester thereof is reacted with anaminoalkan ol

    H.sub.2 N--Z'--OH

wherein Z' is C₁ -C₈ straight or branched alkylene, e.g. 2-aminoethanol,to afford the corresponding intermediate alcohol, e.g. in the case of2-aminoethanol, an intermediate of the formula ##STR1066## That alcoholis then reacted with a drug containing one or more --COOH functions, inthe presence of a suitable coupling agent such asdicyclohexylcarbodiimide. The compound thus obtained is then quaternizedand subsequently reduced as described above in Method A.

Analogous starting materials can be readily prepared by reacting theselected aminoalkanol with picolinic acid, isonicotinic acid,3-quinolinecarboxylic acid, 4-isoquinolinecarboxylic acid or the like toafford the desired intermediate, which can then be quaternized andsubsequently reduced as described above.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Drugssuch as methicillin, ticarcillin, oxacillin, dicloxacillin, glyoxylicacid sulfonyl hydrazone, 5-methyltetrahydrohomofolic acid,phenoxymethylpenicillin, fenbufen, fenoprofen, idoprofen, ketoprofen,fluprofen, bucloxic acid, tolmetin, alclofenac, fenclozic acid,ibufenac, meclofenamic acid, flufenamic acid, flufenisal, clonixin,carprofen, etodolac, flutiazin, pirprofen, furosemide, cefoxitin andclorazepate may be similarly derivatized.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1067##      ##STR1068##      ##STR1069##      ##STR1070##      ##STR1071##      ##STR1072##      ##STR1073##      ##STR1074##      ##STR1075##      ##STR1076##      ##STR1077##      ##STR1078##      ##STR1079##      ##STR1080##      ##STR1081##      ##STR1082##      ##STR1083##      ##STR1084##      ##STR1085##      ##STR1086##      ##STR1087##      ##STR1088##      ##STR1089##      ##STR1090##      ##STR1091##      ##STR1092##      ##STR1093##      ##STR1094##      ##STR1095##      ##STR1096##      ##STR1097##      ##STR1098##      ##STR1099##      ##STR1100##      ##STR1101##      ##STR1102##      ##STR1103##      ##STR1104##      ##STR1105##      ##STR1106##      ##STR1107##      ##STR1108##      ##STR1109##      ##STR1110##      ##STR1111##      ##STR1112##      ##STR1113##      ##STR1114##      ##STR1115##      ##STR1116##      ##STR1117##      ##STR1118##      ##STR1119##      ##STR1120##      ##STR1121##      ##STR1122##      ##STR1123##      ##STR1124##      ##STR1125##      ##STR1126##      ##STR1127##      ##STR1128##      ##STR1129##      ##STR1130##      ##STR1131##      ##STR1132##      ##STR1133##      ##STR1134##      ##STR1135##      ##STR1136##      ##STR1137##      ##STR1138##      ##STR1139##      ##STR1140##      ##STR1141##      ##STR1142##      ##STR1143##      ##STR1144##      ##STR1145##      ##STR1146##      ##STR1147##      ##STR1148##      ##STR1149##      ##STR1150##      ##STR1151##      ##STR1152##      ##STR1153##      ##STR1154##      ##STR1155##      ##STR1156##      ##STR1157##      ##STR1158##

Method R

This is a variation of Method Q used when the drug contains one or more--OH or --SH functions which are to be protected.

The drug is first reacted with excess trimethylacetyl chloride toconvert the hydroxy group(s) to pivalyloxy group(s). (Various otherhydroxy protecting groups may be introduced in similar fashion.) Theprotected drug is then reacted with the intermediate alcohol ##STR1159##in the presence of dicyclohexylcarbodiimide or other appropriate agentfor coupling the --COOH function of the drug to the hydroxy function ofthe depicted intermediate. (Other intermediate alcohols can be employed,e.g. as described in Method Q.) The resultant compound is thenquaternized and the quaternary subsequently reduced as in Method A.

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Drugssuch as clorazepate, 4-hydroxy-2-n-propylpentanoic acid,3-hydroxy-2-n-propylpentanoic acid and captopril may be similarlyderivatized.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1160##      ##STR1161##      ##STR1162##      ##STR1163##      ##STR1164##      ##STR1165##      ##STR1166##      ##STR1167##      ##STR1168##      ##STR1169##      ##STR1170##      ##STR1171##      ##STR1172##      ##STR1173##      ##STR1174##      ##STR1175##      ##STR1176##      ##STR1177##

Method S

This is a variation of Method Q used when the drug contains one or moreamino functions which are to be protected. Generally, the amino group isprotected prior to any reaction of the carboxyl function; typically, abenzyloxycarbonyl group is introduced in conventional manner to protectthe amino function and then the N-protected drug is reacted with theintermediate alcohol as is Methods Q and R. Removal of the protectinggroup, in conventional fashion, takes place when protection is no longerneeded, generally before formation of the formula (II) quaternary andsubsequent reduction to the compound of formula (I).

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). GABA andother omega amino acids, other natural amino acids such as glycine,tyrosine, aspartic acid and glutamic acid, small peptides (e.g. met⁵-enkephalin and leu⁵ -enkephalin and other 2-20 amino acid unitpeptides) and the like may be similarly derivatized.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1178##      ##STR1179##      ##STR1180##      ##STR1181##      ##STR1182##      ##STR1183##      ##STR1184##      ##STR1185##      ##STR1186##      ##STR1187##      ##STR1188##      ##STR1189##      ##STR1190##      ##STR1191##      ##STR1192##      ##STR1193##      ##STR1194##      ##STR1195##      ##STR1196##      ##STR1197##      ##STR1198##      ##STR1199##      ##STR1200##      ##STR1201##      ##STR1202##      ##STR1203##      ##STR1204##      ##STR1205##      ##STR1206##

Method T

This variation of Method Q can be used when the drug contains one ormore NH₂ and OH functions which are to be protected. The protectinggroups, for example, benzyloxycarbonyl for amino functions andpivalyloxy for hydroxyl functions, are introduced as described inMethods R and S, in the sequence considered most convenient. (Obviously,other protecting groups can be introduced instead.) The carboxylfunction(s) are then derivatized according to Method Q. Typically, thehydroxy protecting group(s) are introduced first and are retainedthroughout the process, while the amino protecting group(s) aregenerally removed earlier, frequently prior to formation of thequaternary derivative of formula (II).

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I). Aminoacids containing hydroxyl functions (e.g. tyrosine) and small peptidescontaining such amino acids are also prime candidates for derivation inaccord with this method.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1207##      ##STR1208##      ##STR1209##      ##STR1210##      ##STR1211##      ##STR1212##      ##STR1213##      ##STR1214##      ##STR1215##

Method U

The drug is first reacted with ethylene glycol (or otherdihydroxyalkanol having up to 8 carbon atoms), in the presence of asuitable coupling agent such as dicyclohexylcarbodiimide, to convert the--COOH function(s) to the corresponding

    --COOCH.sub.2 CH.sub.2 OH

(or other ##STR1216## group(s). That intermediate is then reacted with acompound of the formula ##STR1217## or the like, prepared as describedin Method J, in the presence of a coupling agent such asdicyclohexylcarbodiimide, to give the desired quaternary derivative offormula (II). Subsequent reduction to the corresponding dihydroderivative of formula (I) proceeds as described in Method A.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q.

The procedure described above may be repeated utilizing a reactant ofthe formula ##STR1218## or the like, prepared as described in Method J,in place of the intermediate of the formula ##STR1219##

This procedure may also be adapted to preparation of derivatives of thedrugs mentioned with Methods R, S and T.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1220##      ##STR1221##      ##STR1222##      ##STR1223##      ##STR1224##      ##STR1225##      ##STR1226##      ##STR1227##      ##STR1228##      ##STR1229##      ##STR1230##      ##STR1231##      ##STR1232##      ##STR1233##      ##STR1234##      ##STR1235##      ##STR1236##      ##STR1237##      ##STR1238##      ##STR1239##      ##STR1240##

Method U'

The drug is reacted with excess alcohol of the formula ##STR1241##wherein n=1-3, preferably 2, to convert the --COOH function to thecorresponding ##STR1242## ester grouping. The resultant quaternary offormula (II) is then reduced as described in Method A. when the drugcontains more than one reactive carboxyl function, reaction conditionsmay be varied so that more than one carboxyl function will be convertedto ester groupings. (The starting alcohol may be prepared fromnicotinamide, e.g. when n=2, by reacting 2-iodoethanol withnicotinamide.)

The representative drugs depicted below may be derivatized in thismanner to the corresponding compounds of formulas (II) and (I), as maythe remaining compounds mentioned with Method Q.

The procedure described in the first paragraph of this method mayutilize a starting alcohol of the formula ##STR1243## (prepared frompicolinamide or isonicotinamide, respectively) in place of the startingalcohol depicted in the first paragraph, to afford the correspondingderivatives of the drugs indicated with this method.

This procedure may also be adapted to preparation of derivatives of thedrugs mentioned with Methods R, S and T.

      Starting Material [DQC].sup.+ [DDHC]      ##STR1244##      ##STR1245##      ##STR1246##      ##STR1247##      ##STR1248##      ##STR1249##      ##STR1250##      ##STR1251##      ##STR1252##      ##STR1253##      ##STR1254##      ##STR1255##      ##STR1256##      ##STR1257##      ##STR1258##      ##STR1259##      ##STR1260##      ##STR1261##      ##STR1262##      ##STR1263##      ##STR1264##      ##STR1265##      ##STR1266##      ##STR1267##      ##STR1268##      ##STR1269##      ##STR1270##      ##STR1271##      ##STR1272##      ##STR1273##      ##STR1274##      ##STR1275##      ##STR1276##      ##STR1277##      ##STR1278##      ##STR1279##      ##STR1280##      ##STR1281##      ##STR1282##      ##STR1283##      ##STR1284##      ##STR1285##      ##STR1286##      ##STR1287##      ##STR1288##      ##STR1289##      ##STR1290##      ##STR1291##      ##STR1292##      ##STR1293##      ##STR1294##      ##STR1295##      ##STR1296##      ##STR1297##      ##STR1298##      ##STR1299##      ##STR1300##      ##STR1301##      ##STR1302##      ##STR1303##      ##STR1304##      ##STR1305##      ##STR1306##      ##STR1307##      ##STR1308##      ##STR1309##      ##STR1310##      ##STR1311##      ##STR1312##      ##STR1313##      ##STR1314##      ##STR1315##      ##STR1316##      ##STR1317##      ##STR1318##      ##STR1319##      ##STR1320##      ##STR1321##

Method U"

Method U' is repeated, except that the starting alcohol employed has theformula ##STR1322## (That starting material may be prepared by reactingbromoglucose with nicotinamide.)

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q.

Alternatively, Method U" may utilize a starting alcohol of the formula##STR1323## (prepared by reacting bromoglucose with picolinamide orisonicotinamide), to afford the corresponding derivatives of thecompounds mentioned with Method Q.

This procedure may also be adapted to preparation of derivatives of thedrugs mentioned with Methods R, S and T.

      Starting Material [DQC].sup.+ [DDHC]      ##STR1324##      ##STR1325##      ##STR1326##      ##STR1327##      ##STR1328##      ##STR1329##      ##STR1330##      ##STR1331##      ##STR1332##      ##STR1333##      ##STR1334##      ##STR1335##      ##STR1336##      ##STR1337##      ##STR1338##      ##STR1339##      ##STR1340##      ##STR1341##      ##STR1342##      ##STR1343##      ##STR1344##      ##STR1345##      ##STR1346##      ##STR1347##      ##STR1348##      ##STR1349##      ##STR1350##

Method U"'

Method U' is repeated, except that the starting alcohol employed has theformula ##STR1351## (That starting material may be prepared by reactingnicotinic acid with 1,2-propylene glycol in the presence ofdicyclohexylcarbodiimide.)

The representative drugs listed below may be derivatized in this mannerto the corresponding compounds of formulas (II) and (I), as may theremaining drugs mentioned with Method Q.

The procedure of Method U"' may be repeated using a starting alcohol ofthe formula ##STR1352## in place of the starting alcohol depicted above(prepared in an analogous manner using picolinic acid or isonicotinicacid in place of nicotinic acid in the reaction with 1,2-propyleneglycol), to afford the corresponding derivatives of the drugs indicatedin Method Q.

This procedure may also be adapted to preparation of derivatives of thedrugs mentioned with Methods R, S

      Starting Material [DQC].sup.+ [DDHC]      ##STR1353##      ##STR1354##      ##STR1355##      ##STR1356##      ##STR1357##      ##STR1358##      ##STR1359##      ##STR1360##      ##STR1361##      ##STR1362##      ##STR1363##      ##STR1364##      ##STR1365##      ##STR1366##      ##STR1367##      ##STR1368##      ##STR1369##      ##STR1370##

Method V

A drug containing one --COOH function is reacted with an equivalentamount of inositol, in the presence of dicyclohexylcarbodiimide or othersuitable coupling agent, to convert the --COOH function to a group ofthe structure ##STR1371## Reaction of that intermediate with nicotinicacid, in the presence of a suitable coupling agent, or with an activatedester of nicotinic acid, affords an intermediate in which the original--COOH has been converted to ##STR1372## wherein each R is H or##STR1373## the number of original hydroxy groups esterified varyingwith the amount of nicotinic acid employed. Subsequent quaternizationand reduction are carried out as in Method A.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q which contain a single --COOH function.

Alternatively, the above procedure may be repeated, replacing nicotinicacid with an analogous starting material, e.g. picolinic acid,isonicotinic acid, 3-quinolinecarboxylic acid, 4-isoquinolinecarboxylicacid or the like.

Repetition of the procedure of the first paragraph of this methodutilizing a greater amount of the drug (e.g. 2 to 5 or more moles permole of inositol) provides an intermediate containing from 2 to 5 acidresidues and from 4 to 1 hydroxyl groups. That intermediate is thenreacted with nicotinic acid to convert at least one hydroxyl group tothe corresponding ##STR1374## group. Subsequent formation of thequaternary and reduction proceed as in Method A.

This procedure may also be adapted to preparation of derivatives ofdrugs mentioned with Methods R, S and T.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1375##      ##STR1376##      ##STR1377##      ##STR1378##      ##STR1379##      ##STR1380##      ##STR1381##      ##STR1382##      ##STR1383##      ##STR1384##      ##STR1385##      ##STR1386##      ##STR1387##      ##STR1388##      ##STR1389##      ##STR1390##      ##STR1391##      ##STR1392##      ##STR1393##      ##STR1394##      ##STR1395##      ##STR1396##      ##STR1397##      ##STR1398##      ##STR1399##      ##STR1400##      ##STR1401##      ##STR1402##      ##STR1403##      ##STR1404##

Method W

The drug is first reacted with 1,2-propylene glycol (or otherdihydroxyalkanol having up to 8 carbon atoms), in the presence of asuitable coupling agent such as dicyclohexylcarbodiimide, to convert the--COOH function(s) to the corresponding ##STR1405## (or other##STR1406## group(s). The resultant intermediate is then reacted withnicotinic acid, in the presence of an appropriate coupling agent, orwith an activated ester of nicotinic acid, to give an intermediat of thepartial formula ##STR1407## Subsequent quaternization and reduction arecarried out as in Method A.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q.

Alternatively, the above procedure may be repeated, replacing nicotinicacid with an analogous starting material, e.g. picolinic acid,isonicotinic acid, 3-quinolinecarboxylic acid, 4-isoquinolinecarboxylicacid or the like.

This process may of course also be adapted to the preparation of drugssuch as those mentioned with Methods R, S and T.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1408##      ##STR1409##      ##STR1410##      ##STR1411##      ##STR1412##      ##STR1413##      ##STR1414##      ##STR1415##      ##STR1416##      ##STR1417##      ##STR1418##      ##STR1419##      ##STR1420##      ##STR1421##      ##STR1422##      ##STR1423##      ##STR1424##      ##STR1425##

Method X

Glucosamine, of the structural formula ##STR1426## is reacted withnicotinic acid, using equimolar amounts of the reactants, in thepresence of a suitable coupling agent such as dicyclohexylcarbodiimide,or with an activated ester of nicotinic acid. The resultant intermediateof the formula ##STR1427## is then reacted with a drug containing onereactive --COOH function, in the presence of dicyclohexylcarbodiimide orother appropriate coupling agent, replacing one or more of the hydroxygroups with acid residue(s), the number of groups replaced varying withthe relative amounts of reactants used.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q which contain a single --COOH group.

Alternatively, the above procedure may be repeated, replacing nicotinicacid with an analogous starting material, e.g. picolinic acid,isonicotinic acid, 3-quinolinecarboxylic acid, 4-isoquinolinecarboxylicacid or the like.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1428##      ##STR1429##      ##STR1430##      ##STR1431##      ##STR1432##      ##STR1433##      ##STR1434##      ##STR1435##      ##STR1436##      ##STR1437##      ##STR1438##      ##STR1439##      ##STR1440##      ##STR1441##      ##STR1442##      ##STR1443##      ##STR1444##      ##STR1445##      ##STR1446##      ##STR1447##      ##STR1448##      ##STR1449##      ##STR1450##      ##STR1451##

Method Y

The procedure of Method W is repeated, using ethylene glycol in place of1,2-propylene glycol.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q.

Alternatively, nicotinic acid may be replaced in this process with ananalogous starting material, as described in the third paragraph ofMethod W, and/or adapted to the preparation of derivatives of drugs suchas those mentioned with Methods R, S and T.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1452##      ##STR1453##      ##STR1454##      ##STR1455##      ##STR1456##      ##STR1457##      ##STR1458##      ##STR1459##      ##STR1460##      ##STR1461##      ##STR1462##      ##STR1463##      ##STR1464##      ##STR1465##      ##STR1466##      ##STR1467##      ##STR1468##      ##STR1469##      ##STR1470##      ##STR1471##      ##STR1472##      ##STR1473##      ##STR1474##      ##STR1475##      ##STR1476##      ##STR1477##      ##STR1478##      ##STR1479##      ##STR1480##      ##STR1481##      ##STR1482##      ##STR1483##      ##STR1484##      ##STR1485##      ##STR1486##      ##STR1487##      ##STR1488##      ##STR1489##      ##STR1490##      ##STR1491##      ##STR1492##      ##STR1493##      ##STR1494##      ##STR1495##      ##STR1496##      ##STR1497##      ##STR1498##      ##STR1499##      ##STR1500##      ##STR1501##      ##STR1502##      ##STR1503##      ##STR1504##

Method Z

The process of the first paragraph of Method Q is repeated, using anaminoalkanol of the formula ##STR1505## in place of 2-aminoethanol.

The drugs depicted below may be derivatized in this manner to thecorresponding compounds of formulas (II) and (I), as may the remainingdrugs mentioned with Method Q.

The process variation described in the second paragraph of Method Q mayalso be applied to Method Z.

This process may of course also be adapted to the preparation ofderivatives of drugs such as those mentioned with Methods R, S and T.

      STARTING MATERIAL [DQC].sup.+ [DDHC]      ##STR1506##      ##STR1507##      ##STR1508##      ##STR1509##      ##STR1510##      ##STR1511##      ##STR1512##      ##STR1513##      ##STR1514##      ##STR1515##      ##STR1516##      ##STR1517##      ##STR1518##      ##STR1519##      ##STR1520##      ##STR1521##      ##STR1522##      ##STR1523##

IV. Methods for Salt Formation

An ether solution of a compound of formula (I) is treated with anequivalent amount of anhydrous p-toluenesulfonic acid dissolved in dryether. Mixing at room temperature is continued until the iminium saltprecipitates out of solution. The salt is then removed by filtration.

Imminium salts which may be prepared in this manner include thosederived from the following representative compounds of formula (I):##STR1524##

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given, it being understoodthat same are intended only as illustrative and in nowise limitative.

In the examples immediately to follow, all melting points were taken ona Mel-Temp apparatus and are not corrected. Elemental analyses wereperformed at Atlantic Microlab, Inc., Atlanta, Ga. Infrared spectra weredetermined using a Beckman Acculab 1 double-beam recordingspectrophotometer. NMR spectra were determined by means of a Varian T60Aor FX100 spectrometer. All chemical shifts reported are in δ units(parts per million) relative to tetramethylsilane. Ultravioletabsorbance spectra were determined using a Cary Model 219spectrophotometer. HPLC analysis were performed on Waters AssociatesLiquid chromatograph with Mode 6000A solvent delivery system, Model U6Kinjector and Model 440 absorbance detector. And in all cases where Anal.C, H, N is indicated, the elementary analysis of the compound was foundwithin ±0.4 of the calculated value.

EXAMPLE 1 Preparation of N-(β-Phenethyl)nicotinamide

To 10.25 g (0.083 mol) of nicotinic acid, 27.5 ml of thionyl chloridewere gradually added. The mixture was stirred at room temperature for 10min and then refluxed while stirring for 2 hrs. Excess thionyl chloridewas then distilled off under reduced pressure. Dry benzene (over sodium,50 ml) was added and then distilled off under reduced pressure (toremove traces of SOCl₂). A white crystalline acid chloride hydrochloridewas left, which was used as such for the preparation of amides.

To the solid acid chloride hydrochloride, 150 ml of dry and freshlydistilled pyridine were added. To the stirred mixture, 10.45 ml (0.083mol) of phenethylamine were dropped over 15 min. The mixture was thenheated on a water bath while stirring for 2 hrs. Pyridine was distilledoff on rotavap. The brown oily residue was poured onto crushed ice. Thecream-white solid which separated was filtered by suction, washed withcold water and dried in vacuum; yield 13.3 g (70%), m.p. 79°-80° C.; ir(KBr) 3320 (NH) and 1630 cm⁻¹ (C═O), NMR (CDCl₃) δ 8.66 (bs, 1H, C₄pyridine proton), 8.46 (bd, 1H, C₆ pyridine proton), 8.0-7.6 (m, 1H, C₄pyridine proton), 7.33-6.90 (bs, 6H, C₆ H₅ +C₅ pyridine proton),7.0-6.57 (hump, 1H, CONH), 3.73 (g, 2H, ##STR1525## 2.97 (t, 2H, CH₂--φ). Anal. (C₁₄ H₁₄ N₂ O) C, H, N.

EXAMPLE 2 Preparation of 1-Benzyl-3-(N-η-phenethyl)carbamoylpyridiniumbromide

To a solution of 2.26 g (0.01 mol) of N-(β-phenethyl)nicotinamide in 5ml of methanol, 1.4 ml (0.0114 mol) of benzyl bromide were added. Themixture was refluxed for 3 hours. Methanol was distilled off on rotavap.The yellow, oily residue left was scratched when it suddenly solidifiedinto buff, gritty solid. Crystallized from acetone/ether, yield 3.7 g(95%), m.p. 142°-144° C., U.V. max (buffer pH 7.4) 210 and 260 nm; ir(KBr) 3180 (NH) and 1670 cm⁻¹ (C═O). NMR (CDCl₃ /DMSO-d₆) δ 10.26 (bs,1H, C₂ pyridine proton), 9.53-8.90 (m, 2H, C₆ and C₄ pyridine protons),8.16-7.13 (m, 12H, 2C₆ H₅ +CONH+C₅ pyridine protons), 6.13 (s, 2H,##STR1526## 3.96-3.50 (m, 2H, --N--CH₂), 3.26-2.83 (m, 2H, CH₂ --φ).Anal. (C₂₁ H₂₁ BrN₂ O) C, H, N.

EXAMPLE 3 Preparation of 1-Methyl-3-(N-β-phenethyl)carbamoyl iodide

To a solution of 2.26 g (0.01 mol) of N-(β-phenethyl)nicotinamide in 5ml of methanol, 1.3 ml (0.02 mol) in methyl iodide were added. Themixture was refluxed for 3 hrs. Methanol was distilled off on rotavapand the yellow, oily residue was cooled and scratched when a yellowgritty solid was obtained. Crystallized from acetone, yield 3.5 g (95%),m.p. 134°-136° C., U.V. max (buffer pH 7.4) 210, 225 and 226 nm. Ir(KBr) 3240 (NH) and 1665 cm⁻¹ (C═O). NMR (CDCl₃ /DMSO-d₆) δ 9.63 (s, 1H,C₂ pyridine proton), 9.4-8.9 (m, 2H, C₄ and C₆ pyridine protons),8.32-8.06 (m, 1H, C₅ pyridine proton), 4.6 (s, 3H, ##STR1527## 3.9-3.46(m, 2H, --N--CH₂), 3.2-2.8 (m, 2H, CH₂ --φ). Anal. (C₁₅ H₁₇ IN₂ O) C, H,N.

EXAMPLE 4 Preparation of1-Benzyl-3-(N-β-phenethyl)carbamoyl-1,4-dihydropyridine

To a solution of 3.97 g (0.01 mol) of1-benzyl-3-(N-β-phenethyl)carbamoylpyridinium bromide in 200 ml ofdeaerated water, 5.0 g (0.06 mol) of sodium bicarbonate and 200 ml ofether were added. The mixture was stirred in an ice bath and 7.1 g (0.04mole) of sodium dithionate were added gradually over a period of 5 min.The mixture was stirred for 3 hrs under nitrogen. The ether layer wasthen separated, washed with water, dried with Na₂ SO₄ and distilledunder vacuo. Yield 2.3 g (72%) of bright yellow, viscous oil wasobtained which gave positive test for dihydropyridine with alcoholicsilver nitrate solution. U.V. max (buffer pH 7.4) 210 and 355 nm. NMR(CDCl₃) δ two overlapping singlets at 7.2 (10H, 2C₆ H₅), 7.1 (bs, 1H, C₂pyridine proton), 5.68 (doublet of doublets, 1H, J=8 and 2 cps, C₆pyridine proton), 6.4-5.0 (hump, 1H, CONH), 4.84-4.60 (m, 1H, C₅pyridine proton), 4.35 (s, 2H, N--CH₂), 3.5 (q, 2H, J-7.0, ##STR1528##3.0 (bs, 2H, C₄ pyridine proton) and 2.8 (t, 2H, J=7.0, CH₂ --φ).

EXAMPLE 5 Preparation of1-Methyl-3-(N-β-phenethyl)carbamoyl-1,4-dihydropyridine

By the similar method described above,1-methyl-3-(N-β-phenethyl)carbamoyl iodide (3.68 g, 0.01 mol) wasreduced using sodium dithionate (7.1 g, 0.04 mol) and sodium bicarbonate(5.0 g, 0.06 mol). Yield 1.8 g (76%) of bright yellow, viscous oil whichreduced alcoholic silver nitrate solution. U.V. max (buffer ph 7.4) 210,290 and 360 nm; NMR (CDCl₃) δ 7.2 (s, 5H, C₆ H₅), 6.9 (bs, 1H, C₂pyridine proton), 5.6 (doublet of doublets, 1H, J=8, 2 cps, C₆ pyridineproton), 5.3-5.1 (hump, 1H, CONH), 4.5-4.7 (m, 1H, C₅ pyridineprotons+N--CH₃ +CH₂ --φ). Anal. (C₁₅ H₁₈ N₂ O) C, H, N.

EXAMPLE 6 Preparation of Diethyl 3,5-pyridinedicarboxylate

To suspension of 8.35 g (0.05 mol) of 3,5-pyridinedicarboxylic acid in30 ml of absolute ethanol, 10 ml of concentrated sulfuric acid weredropped while stirring. The mixture was then refluxed on a water bathfor 5 hrs and poured onto crushed ice. The solution was then madealkaline by the addition of solid KHCO₃ in small amounts. A white solidwhich separated was filtered, washed with water and dried. M.p. 42°-44°C. The mother liquid was extracted with CH₂ Cl₂ when another crop of thediester was obtained. The overall yield of the crude ester was 9.1 g(82%) of sufficient purity for the examples to follow. NMR (CDCl₃) δ9.62 (d, 2H, J-2 Hz, C₂ and C₆ pyridine protons), 8.76 (t, 1H, J=2 Hz,C₄ pyridine proton), 4.43 (q, 4H, J=7 Hz, 2 OCH₂), 1.41 (t, 6H, J=7 Hz,2 CH₃).

EXAMPLE 7 Preparation of 5-Carboethoxy-3-pyridinecarboxylic acid

To a solution of 10 g (0.045 mol) of diethyl 3,5-pyridinedicarboxylatein 75 ml of ethyl alcohol, 25 ml of 2N alcoholic KOH were added whilestirring. Stirring was continued for 1/2 hour at room temperature. Tothe mixture, 12.5 ml of 4N HCl were added while stirring. The solidwhich separated was filtered and washed with alcohol. The combinedfiltrate and washings were distilled on rotovap and the residue waswashed with water, filtered and crystallized from ethanol. Yield 7.5 g(86%), m.p. 180°-182° C., NMR (CDCl₃ /DMSO-d₆) δ 10.56 (bs, 1H, COOH),9.26 (d, 2H, J=2 Hz, C₂ and C₆ pyridine protons), 8.75 (t, 1H, J=2 Hz,C₄ pyridine protons), 4.4 (q, 2H, J=7 Hz, O--CH₂), 1.42 (t, 3H, J=7 Hz,CH₃).

EXAMPLE 8 Preparation of5-Carboethoxy-3-(N-β-phenethyl)carbamoylpyridine

To 10 g (0.05 mol) of 5-carboethoxy-3-pyridinecarboxylic acid, 30 ml ofthionyl chloride were added and the mixture was warmed on a water bathwhile stirring until clear (≅3 hrs). Excess thionyl chloride wasdistilled under vacuum. The residue was cooled to room temperature and50 ml of sodium-dry benzene was added. The solution was cooled in an icebath and a solution of 6.2 g (0.051 mol) of phenethylamine and 4 ml ofpyridine in 50 ml of dry benzene was dropped while stirring over 1 hrand the mixture was left overnight at room temperature. The mixture wasthen washed with water until free from Cl⁻ (tested by AgNO₃ TS). Theorganic layer was dried with Na₂ SO₄ and distilled. The residue wascrystallized from ether/pet. ether mixture. Yield 9.0 g (67%), m.p.159°-161° C.; ir (KBr) 3300 (NH), 1725 (ester CO) and 1650 cm⁻¹ (amideCO), NMR (CDCl₃) δ 9.13-9.96 (two doublets, 2H, J=2 Hz, C₂ and C₆pyridine protons), 8.53 (t, 1H, J=2 Hz, C₄ pyridine proton), 7.16 (s,6H, C₆ H₅ +CONH), 4.36 (q, 2H, J=7 Hz, OCH₂), 3.4 (q, 2H, J=7 Hz,N--CH₂), 2.9 (5, 2H, J=7 Hz, CH₂ --φ), 1.33 (t, 3H, J=7 Hz, CH₃). Anal.(C₁₇ H₁₈ N₂ O₃) C, H, N.

EXAMPLE 9 Preparation of5-Carboethoxy-1-methyl-3-(N-β-phenethyl)carbamoylpyridinium iodide

To a solution of 2.9 g (0.01 mol) of5-carboethoxy-3-(N-β-phenethyl)carbamoylpyridine in 5 ml of acetone, 3ml of methyl iodide were added. The mixture was refluxed while stirringfor 8 hrs and then left overnight. The yellow crystalline solid whichprecipitated was filtered, washed with acetone, dried and crystallizedfrom acetone. Weight 3.5. g (82%), m.p. 168°-170° C., ir (KBr) 3250(NH), 1725 (ester CO) and 1670 cm⁻¹ (amide CO), U.V. max (buffer pH 7.4)268 (weak plateau) and 268 nm (ε=53, 667), NMR (DMSO-d₆) δ 9.53 (bs, 2H,C₂ and C₆ pyridine protons), 9.33-9.10 (m, 1H, C₄ pyridine proton), 7.16(s, 5H, C₆ H₅), 4.63-4.26 (complex multiplet, 5H, ##STR1529## 3.56 (q,2H, J=6 Hz, ##STR1530## 2.90 (t, 2H, J=6, CH₂ --φ), 1.4 (t, 3H, J=7 Hz,CH₃). Anal. (C₁₈ H₂₁ IN₂ O₃) C, H, N.

EXAMPLE 10 Preparation of5-Carboethoxy-1-methyl-3-(N-β-phenethyl)carbamoyl-1,4-dihydropyridine

This compound was prepared following the same procedure as in Example 4using 1.0 g (0.002 mol) of5-carboethoxy-1-methyl-3-(N-β-phenethyl)carbamoylpyridinium iodide, 1.0g (0.012 mol) sodium bicarbonate and 1.42 g (0.008 mol) sodiumdithionite. Yield, 0.60 g (84%) of orange-yellow viscous oil whichreduced alcoholic silver nitrate, but very sowly. U.V. max (buffer pH7.4) 205 and 390 nm. NMR (CDCl₃) 7.33 (s, 5H, C₆ H₅), 7.0 (s, 2H, C₂ andC₆ pyridine protons), 5.8-5.3 (hump, 1H, CONH), 4.2 (q, 2H, J=7,O--CH₂), 3.66 (q, 2H, J=7 Hz, ##STR1531## 3.16 (bs, 2H, C₄ pyridineproton), 3.0 (q, 2H, J=7, CH₂ --φ), 1.4 (t, 3H, J=7, CH₃).

EXAMPLE 11 Preparation of 3,5-Di(N-β-phenethyl)carbamoylpyridine

To a solution of 2.53 g (0.01 mol) of diethyl 3,5-pyridinedicarboxylatein 10 ml of methanol, 3.0 g (0.025 mol) of phenethylamine were added.The mixture was refluxed overnight and then distilled. The residue waswashed with very dilute HCl solution and water, dried and crystallizedform ethanol. Yield 2.9 g (80%), m.p. 189°-190° C. NMR (CDCl₃) δ 9.00(d, J=2 Hz, 2H, 2,6-dipyridyl), 8.33 (5, J=2, 1H, 4-pyridyl), 7.30 (s,10H, 2 C₆ H₅), 6.93-6.40 (hump, 2H, 2 COHN), 3.83 (q, J=7, 4H, 2--N--CH₂), 3.00 (t, J=7, 4H, 2 --CH₂ --φ). Anal. (C₂₃ H₂₃ N₃ O₂) C, H,N.

EXAMPLE 12 Preparation of 1-Methyl-3,5-di(N-β-phenethyl)carbamoylpyridinium iodide

To a solution of 2.0 g (5.3 mmol) of3,5-di(N-β-phenethyl)carbamoylpyridine in 10 ml of acetone, 2 ml ofmethyl iodide were added and the mixture was refluxed for 24 hrs. Theyellow crystalline solid which separated was filtered, washed withacetone and dried. Weight 1.4 g (51%), m.p. 186°-188° C. U.V. spectrumof a solution in phosphate buffer 7.4 showed a plateau at 275 nm, ashoulder at 225 nm and a sharp peak at 203 nm (ε=67,356). Ir (KBr) 3240(NH), 1665 and 1650 cm⁻¹ (twin band, C═O). NMR (CDCl₃ /D₂ O) δ 9.35 (d,2H, J=2, C₂ and C₆ pyridine protons), 8.56 (d, 1H, J=2 Hz, C₄ pyridineproton), 7.20 (s, 10H, 2 C₆ H₅), 4.56 (s, 3H, ##STR1532## 3.66 (t, 4H,J=7 Hz, 2 --N--CH₂), 2.96 (t, 4H, J=7 Hz, 2 CH₂ --φ). Anal. (C₂₄ H₂₆ IN₃O₂).

EXAMPLE 13 Preparation of1-Methyl-3,5-di(N-β-phenethyl)carbamoyl-1,4-dihydropyridine

This compound was prepared following the same procedure as in Example 4,using 1 g (0.002 mol) of 1-methyl-3,5-di(N-β-phenethyl)carbamoylpyridinium iodide, 1.0 g (0.012 mol) sodium bicarbonate and 1.4 g (0.008mol) sodium dithionite. Yield 0.65 g (86%) of orange-yellow semisolidwhich could not be crystallized. Its alcoholic solution shows a slowreduction with alcoholic silver nitrate solution. U.V. max (buffer pH7.4) 388 and 210 nm. NMR (CDCl₃) 7.13 (s, 5H, C₆ H₅), 6.76 (s, 1H, C₂pyridine protons), 3.51 (q, 4H, J=7 Hz, 2 ##STR1533## 3.06-2.60 (m, 9H,O--CH₂ +C₄ pyridine proton +N--CH₃).

EXAMPLE 14 Preparation of N-Nicotinoyldopamine (compound 7)

To a pyridine solution containing 11.7 g (0.05 mol) dopaminehydrobromide and 6.15 g (0.05 mol) nicotinic acid at 0° C. were added10.3 g (0.05 mol) dicyclohexylcarbodiimide (DCC). The reaction mixturewas stirred at room temperature for 24 hours and the formeddicyclohexylurea was removed by filtration. The pyridine was removed invacuo and the residue was crystallized from water at 0° C. The productwas isolated by filtration and dried over phosphorous pentoxide.Recrystallization from isopropanol gave 9.0 g (0.035 mol), 70%N-nicotinoyldopamine, m.p. 159°-162° C.; aqueous solution of thecompound gave a green color with Fe⁺³ and reduced AgNO₃ ; ir (KBr) 3300,2960, 1725, 1630, 1590, 1520, 1430, 1290, 1190, 1115, 720 and 710 cm⁻¹ ;NMR (d₆ -DMSO) β 9.25-6.25 (m, 7H), 3.3 (m, 2H) and 2.65 (m, 2H) ppm.Anal. (C₁₄ H₁₄ N₂ O₃) C, H, N.

EXAMPLE 15 Preparation of3-{N-[β-(3,4-Diacetoxyphenyl)ethyl]}carbamoylpyridine

To an ice cold suspension of 2.06 g (8 mmol) finely powderednicotinoyldopamine in 50 ml of chloroform, 1.56 g (10 mmol) of acetylchloride were dropped while stirring. The mixture was refluxed for 3hrs, then filtered. The filtrate was washed with water until the washingdid not give test for chloride ions with AgNO₃ T.S. Chloroform wasdistilled on rotavap and the residue was crystallized from ether/pet.ether. Yield 2.2 g (81%) NMR (CDCl₃) 8.90 (bs, 1H, C₂ pyridine proton),8.56 (bd, 1H, C₆ pyridine proton), 8.16-7.83 (m, 1H, C₄ pyridineproton), 7.36-7.03 (m, 5H, C₆ H₃ +C₅ pyridine proton +NH), 3.60 (q, 2H,J=7 Hz, ##STR1534## 2.90 (t, 2H, J=7 Hz, --CH₂).

EXAMPLE 16 Preparation of3-{N-[β-(3,4-Dipivalyloxyphenyl)ethyl]}carbamoylpyridine (compound 8c)

To a suspension of 5.16 g (0.02 mol) finely powdered nicotinoyldopaminein 100 ml chloroform, 7.23 g (0.06 mol) trimethylacetyl chloride wereadded under stirring. The mixture was refluxed for 6 hrs and thenfiltered. The filtrate was washed with water free of chloride ions, thenwashed once with a 5% solution of NaHCO₃, then with water. Thechloroform was evaporated and the residue was chromatographed by using asilica gel G column and 2% methanol in chloroform as the eluent. Thefirst fraction was collected and evaporated and the residue wascrystallized from ether/petroleum ether. Yield, 6.2 g (73%) of a whitecrystalline solid, m.p. 112°-114° C., NMR (CDCl₃) δ 9.06 (bs, 1H, C₂pyridine proton), 8.73 (bd, 1H, C₆ pyridine proton), 8.30-8.13 (m, 1H,C₄ pyridine proton), 7.46-7.10 (m, 5H, C₆ H₃ +C₅ pyridine proton+CONH),3.66 (q, 2H, J=6.25 Hz, --N--CH₂), 3.0 (t, 2H, J=6 Hz, --CH₂), 1.41 (s,18H, 2--C(CH₃)₃). Anal. Calcd for C₂₄ H₃₀ N₂ O₅ : C, 67.58; H, 7.09; N,6.56. Found: C, 67.61; H, 7.10; N, 6.54.

EXAMPLE 17 Preparation of1-Methyl-3-{N-[β-(3,4-dihydroxyphenyl)ethyl)]}carbamoylpyridinium iodide(compound 6a)

To a solution of 1.26 g (5 mmol) of nicotinoyldopamine (7) in 10 ml ofacetone, 1.41 g (10 mmol) of methyl iodide were added and the mixturewas refluxed under stirring for 6 hrs. The acetone was removed and theresidue was crystallized from methanol/ether. Yield, 1.7 g (87%), m.p.155°-157° C.(dec). Aqueous solution gave a green color with Fe⁺³, NMR(D₂ O) δ 9.30-8.28 (ms, 4H, C₅ H₄ N⁺), 7.00 (bs, 3H, C₆ H₃), 4.60 (s,3H, --N⁺ --CH₃), 3.80 (t, 2H, J=7 Hz, --N--CH₂), 2.93 (t, 2H, J=7 Hz,CH₂). Anal. Calcd for C₁₅ H₁₇ IN₂ O₃.H₂ O: C, 43.11; H, 4.55; N, 6.70.Found: C, 43.83; H, 4.23; N, 6.81.

EXAMPLE 18 Preparation of1-Methyl-3-{N-[β-(3,4-diacetoxyphenyl)ethyl]}carbamoylpyridinium iodide(compound 6b)

To a solution of 1.71 g (5 mmol) of3-{N-[β-(3,4-diacetoxyphenyl)ethyl]}carbamoylpyridine (prepared likecompound 8c), 1.41 g (10 mmol) of methyl iodide were added and themixture was refluxed overnight under stirring. The acetone solution wasthen decanted from the insoluble oily residue. Ether was added to theacetone solution and the solid which separated was crystallized fromacetone/ether. Yield, 1.9 g (78%) of yellow crystalline needles, m.p.171°-173° C. U.V. (methanol) 215, 265 nm; NMR (D₂ O) δ 8.86-7.63 (ms,4H, C₅ H₄ N⁺), 6.66 (bs, 3H, C₆ H₃), 4.4 (s, 3H, --N⁺ --CH₃), 3.50 (t,2H, --N--CH₂), 3.03 (t, 2H, CH₂), 2.21 (bs, 6H, 2 COCH₃). Anal. Calcdfor C₁₉ H₂₁ IN₂ O₅ : C, 47.12; H, 4.37; N, 5.78. Found: C, 47.23; H,4.38; N, 5.78.

EXAMPLE 19 Preparation of1-Methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]}carbamoylpyridiniumiodide (compound 6c)

To a solution of 5.0 g (11.7 mmol) of compound 8c in 20 ml of acetone,3.3 g (23.4 mmol) of methyl iodide were added and the mixture wasrefluxed under stirring for 6 hrs, then cooled. The orange crystallinesolid which separated was filtered, washed with ether and crystallizedfor acetone/ether. Yield, 5.6 g (85%), m.p. 163°-165° C. U.V. (buffer pH7.4) 270, 215 nm. NMR (DMSO-d₆) δ 7.68-7.06 (ms, 7H, C₅ N₄ N⁺ +C₆ H₃+NH), 4.56 (s, 3H, --N⁺ --CH₃), 3.42 (q, 2H, J=7 Hz, --N--CH₂), 3.19 (t,2H, J=7 Hz, CH₂), 1.32 (s, 18H, 2 --C(CH₃)₃). Anal. Calcd for C₂₅ H₃₃IN₂ O₅ : C, 52.82; H, 5.85; N, 4.92. Found: C, 52.76; H, 5.87; N, 4.90.

EXAMPLE 20 Preparation of1-Methyl-3-{N-[β-(4-hydroxy-3-methoxyphenyl)ethyl]}carbamoylpyridiniumiodide (compound 9)

N-nicotinoyl-3-methoxytyramine was prepared by following the procedureused for the preparation of compound 7. The isolated crude amide wasquaternized directly with methyl iodide following the method used forthe preparation of compound 6a. Crystallization from methanol gave ayellow crystalline compound, m.p 192°-194° C. with overall yield of 84%,calculated on the basis of 3-methoxytyramine starting material. NMR (D₂O) closely similar to that of 6a except for the singlet at δ 3.66 forOCH₃.

EXAMPLE 21 Preparation of1-Methyl-3-{N-[β-(3,4-dihydroxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine(compound 5a)

To an ice cold solution of 1.0 g (2.5 mmol) of compound 6a in 200 ml ofdeaerated water, 1.26 g (15 mmol) sodium bicarbonate were added.Nitrogen was bubbled into the mixtue and 1.74 g (10 mmol) of sodiumdithionite were added gradually to the mixture under stirring. Stirringwas continued for 1 hr and the mixture was then extracted twice with 50ml of ether. The ether extract was washed with water, dried withanhydrous Na₂ SO₄ and evaporated to dryness. Yield, 0.36 g (54%) of ayellow solid, m.p. 90°-93° C. (dec.) which gave a green color withferric chloride test and reduced alcoholic AgNO₃ instantly. UV (CH₃ OH)220, 350 nm. NMR (CDCl₃ /D₂ O) δ 7.2-6.9 (ms, 4H, C₆ H₃ +C₂dihydropyridine proton), 5.6 (m, 1H, C₆ dihydropyridine proton), 4.6-4.4(m, 1H, C.sub. 5 dihydropyridine proton), 3.4 (m, 2H, --N--CH₂), 3.1-2.7(m, 7H, N--CH₃ +C₄ dihydropyridine protons+CH₂). Anal. Calcd for C₁₅ H₁₈N₂ O₃.1/2H₂ O: C, 63.59; H, 6.76; N, 9.88. Found: C, 63.56; H, 6.85; N,9.72.

EXAMPLE 22 Preparation of1-Methyl-3-{N-[β-(3,4-diacetoxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine(compound 5b)

To an ice cold solution of 1.4 g (3 mmol) of compound 6b in 200 ml ofdeaerated water, 1.5 g (18 mmol) of sodium bicarbonate was added. Astream of N₂ was bubbled into the mixture and 2.1. g (12 mmol) of sodiumdithionite were gradually added under stirring. Stirring was continuedfor 30 min and then the mixture was extracted with ethyl acetate. Theextract was washed with water, dried with anhydrous Na₂ SO₄ andevaporated to dryness. The yellowish semisolid mass remaining gave afaint green color with ferric chloride test indicating partialhydrolysis of the ester functions. It reduced alcoholic silver nitrateinstantly. U.V. (CH₃ OH) 220, 273 and 355 nm; NMR (CDCl₃ /D₂ O) δ7.13-6.80 (ms, 4H, C₆ H₃ +C₂ dihydropyridine proton), 5.53 (doublet ofdoublets, 1H, C₆ dihydropyridine proton), 4.63-4.46 (m, 1H, C₅dihydropyridine proton), 3.33 (t, 2H, J=6.5 Hz, --N--CH₂), 3.06-2.66 (m,7H, --N--CH₃ +C₄ dihydropyridine proton+CH₂), 1.8 (s, ≅6H, 2COCH₃).

EXAMPLE 23 Preparation of1-Methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine(compound 5c)

To a cold mixture of 2.0 g (3.5 mmol) of compound 6c, 200 ml ofdeaerated water and 100 ml of ethyl acetate, 1.14 g (14 mmol) of sodiumbicarbonate and 2.43 g (14 mmol) of sodium dithionite were added. Themixture was stirred under N₂ for 20 mins. The ethyl acetate layer wasseparated and the aqueous layer was re-extracted with 100 ml of ethylacetate. The combined ethyl acetate was washed with cold deaeratedwater, dried over anhydrous Na₂ SO₄ and distilled on rotovapor. Theviscous yellow oily residue was dissolved in 5 ml of acetone, filteredunder N₂ atmosphere and then evaporated under reduced pressure. Thesolid residue was dried under vacuum over P₂ O₅ in N₂ atmosphere. Itreduced alcoholic AgNO₃ instantaneously and gave no color with DeCl₃test. Yield, 1.3 g (83%) m.p. 45°-48° C.; UV (CH₃ OH) 210 and 355 nm;NMR (CDCl₃) δ 7.04-6.92 (m, 4H, C₆ H₃ +C₂ dihydropyridine proton),5.71-5.61 (doublet of doublets, 1H, C₆ dihydropyridine proton), 4.81(bs, 1H, CONH), 4.60-4.51 (m, 1H, C₅ dihydropyridine proton), 3.53 (q,2H, J=6.3 Hz, --N--CH₂), 2.36 (bs, 2H, C₄ dihydropyridine proton), 2.91(s, 3H, N--CH₃), 2.79 (t, 2H, J=6.3 Hz, CH₂), 1.33 (s, 18H,CO--C(CH₃)₃). Anal. Calcd for C₂₅ H₃₄ N₂ O₅. 11/2H₂ O: C, 63.9; H, 7.93;N, 5.96. Found: C, 63.4; H, 7.81; N, 5.94.

EXAMPLE 24 Preparation of1-Methyl-3-{N-[β-(4-hydroxy-3-methoxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine(compound 10)

This compound was prepared following the same method as for thepreparation of compound 5c. The crude solid obtained showed the same NMR(CDCl₃ /D₂ O) pattern as compound 5a, except for a peak at δ 3.5 for theOCH₃ protons. It was sufficiently pure for the determination of itsretention time following the HPLC method of analysis detailed in Example37 below. No trials were made for its further crystallization orelemental analysis.

EXAMPLE 25 Preparation of N-Nicotinoyltyramine

To an ice cold suspension of 3.69 g (0.03 mol) nicotinic acid in asolution of 5.2 g (0.03 mol) tyramine hydrochloride in 100 ml ofpyridine, 6.18 g (0.03 mol) of dicyclohexylcarbodiimide (DCC) weregradually added while stirring. Stirring was continued at roomtemperature for 24 hrs and the formed dicyclohexylurea was removed byfiltration. The pyridine was removed by distillation in vacuo and theresidue was triturated with cold water, filtered and crystallized from50% aqueous methanol. Yield, 6.25 g (86%), m.p. 179°-181° C. PMR(DMSO-d₆ /D₂ O) δ 9.0-8.66 (m, 2H, C₂ and C₆ pyridine protons),8.33-8.10 (m, 1H, C₄ pyridine proton), 7.66-7.46 (m, 1H, C₅ pyridineproton), 7.23-6.70 (m, rH, C₆ H₄), 3.56 (t, 2H, ##STR1535## 2.90 (t, 2H,CH₂). Anal. (C₁₄ H₁₄ N₂ O₂) C, H, N.

EXAMPLE 26 Preparation of3-{N-[β-(4-pivalyloxyphenyl)ethyl]}carbamoylpyridine

To an ice cold suspension of 4.84 g (0.02 mol) N-nicotinoyltyramine in100 ml chloroform, 3.6 g (0.03 mol) of trimethylacetyl chloride weredropped while stirring. The mixture was refluxed overnight and thenon-reacted nicotinoyltyramine was filtered off. The filtrate was washedwith water until free from chloride ions, washed once with 5% solutionof NaHCO₃ and then with water. Chloroform was evaporated on rotavap andthe residue was crystallized from ether/pet. ether. Yield 3.9 g (60%),m.p. 80°-82° C. PMR (CDCl₃) δ 8.66-6.93 (m, 8H, C₅ H₄ N+C₆ H₄), 3.56 (q,2H, J=7 Hz, ##STR1536## 2.86 (5, 2H, J=7 Hz, CH₂), 1.33 (s, 9H,C--(CH₃)₃).

EXAMPLE 27 Preparation of1-Methyl-3-{N-[β-(4-hydroxyphenyl)ethyl]}carbamoylpyridinium iodide

To a solution of 1.21 g (5 mmol) of nicotinoyltyramine in 10 ml ofacetone, 1.41 g (10 mmol) of methyl iodide were added and the mixturewas refluxed while stirring for 6 hrs. The fine, yellow solid whichseparated was filtered and crystallized from methanol ether. Yield 1.78g (93%), m.p. 208°-210° C. PMR (DMSO-d₆ /D₂ O) δ 9.23-8.26 (m, 4H, C₅ H₄N⁺), 7.33-6.83 (m, 4H, C₆ H₄), 4.50 (s, 3H, ##STR1537## 3.70 (t, J=7 Hz,2H, ##STR1538## 2.93 (t, J=7 Hz, 2H, CH₂).

EXAMPLE 28 Preparation of1-Methyl-3-{N-[β-(4-pivalyloxyphenyl)ethyl]}carbamoylpyridinium iodide

To a solution of 1.63 g (5 mmol) of the product of Example 26 in 10 mlof acetone, 1.41 g (10 mmol) methyl iodide were added and the mixturewas refluxed overnight while stirring. The acetone layer was separatedby decantation and the yellowish, oily residue was crystallized frommethanol/ether. Yield, 1.94 g (83%), m.p. 155°-157° C. PMR (D₂ O) δ9.16-8.00 (m, 4H, C₅ H₄ N⁺), 7.33-6.83 (m, 4H, C₆ H₄), 4.40 (s, 3H, N⁺--CH₃), 3.5 (t, 2H, J=7 Hz, ##STR1539## 2.90 (t, 2H, J=7 Hz, CH₂), 1.30(s, 9H, C--(CH₃)₃). Anal. (C₂₀ H₂₅ N₂ O₃ I) C, H, N.

EXAMPLE 29 Preparation of1-Methyl-3-{N-[β-(4-hydroxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridin

To an ice cold solution of 1.15 g (3 mmol) of the product of Example 27in 200 ml of deaerated water, 1.5 g (18 mmol) sodium bicarbonate wereadded. While the mixture was bubbled with N₂ gas, 2.09 g (12 mmol) ofsodium dithionite were gradually added to the mixture. The mixture wasstirred under N₂ for 1 hr and then extracted twice, each with 100 ml ofethyl acetate. The combined extract was washed with water, dried overanhydrous Na₂ SO₄ and distilled on rotovap. Yield, 0.38 g (50%) ofyellowish semisolid which reduced alcoholic AgNO₃ TS instantaneously.(PMR as expected.)

EXAMPLE 30 Preparation of1-Methyl-3-{N-[β-4-pivalyloxyphenyl)]}carbamoyl-1,4-dihydropyridine

To an ice cold mixture of 2.34 g (5 mmol) of the product of Example 28,200 ml of deaerated water and 100 ml of ethyl acetate, 1.63 g (20 mmol)sodium bicarbonate and 3.47 g (20 mmol) sodium dithionite were addedwhile stirring the mixture. Stirring was continued under N₂ gas for 30min. The ethyl acetate layer was separated and the aqueous layer wasextracted with 100 ml of ethyl acetate. The combined ethyl acetateextract was washed with 100 ml cold deaerated water, dried overanhydrous Na₂ SO₄ and evaporated on rotavap. The viscous, yellow residuewas dissolved in 5 ml of acetone, filtered under N₂ gas through foldedfilter paper and distilled on rotavap. The solid residue was dried undervacuo over P₂ O₅ in N₂ atmosphere. It reduced alcoholic AgNO₃instantaneously. Yield, 1.06 g (62%). (PMR as expected.)

EXAMPLE 31 Preparation of 3,5-Pyridinedicarboxylic acid didecyl esterhydrochloride

3,5-Pyridinedicarboxylic acid (9.6 g, 0.06 mole) was converted to thediacid chloride by treatment with excess SOCl₂. The mixture was refluxedat 100° C. for 6 hrs. Excess SOCl₂ was distilled under reduced pressureand 25 ml of decyl alcohol dissolved in benzene were added. The solutionwas refluxed for 5 hrs after which benzene was distilled and the residuedissolved in ethyl ether. The organic phase was extracted withbicarbonate solution and later dried over Na₂ SO₄. The ethyl ethersolution was acidified with HCl (gas) and 24.2 g of compound (95% yield,m.p. 80°-90° C.) were obtained. 1H (NMR) CDCl₃ /d₆ DMSO δ 9.3 (3H, bs),8.7 (1H, bs), 4.3 (4H, bT) and 1.4 (38H, bm) ppm.

EXAMPLE 32 Preparation of Didecyl 3,5-dicarboxylate-1-methylpyridiniumiodide

The product of Example 31 (10 g, 0.025 mole) was dissolved in an ethylether/bicarbonate solution. The organic phase was rinsed with water anddried over Na₂ SO₄. The solvent was evaporated and the residue wasdissolved in acetone and an excess of methyl iodide was added. Thesolution was refluxed for 8 hrs, after which the solvent was evaporatedand ethyl ether was added to the residue. A yellow solid was obtainedwhich was filtered and rinsed with more ethyl ether. The solid wasrecrystallized from a minimum amount of ethyl acetate to yield 12.5 g(85%) m.p. 104°-105° C. Analytical data: Theory: C, 57.04; H, 8.21.Found: C, 57.18; H, 8.09. Spectrophotometric data in methanol: λ219ε=2.7×10⁴ 1/mol cm; λ277 ε=3.6×10³ 1/mol cm.

EXAMPLE 33

(i) Oxidation by Hydrogen Peroxide:

To 10 ml of 30% H₂ O₂ was added 0.2 g of the dihydropyridine derivative(products of Examples 4, 5, 10 or 13). The mixture was stirred andsamples were taken to check the UV spectrum. Complete oxidation to thecorresponding quaternary salts was observed.

(ii) Oxidation by Silver Nitrate:

To 5 ml of saturated methanolic AgNO₃ solution was added 1 ml of 5%methanolic solution of the dihydropyridine derivative. The mixture wasshaken and left for 5 min for complete precipitation of silver,centrifuged and an aliquot was taken to check the UV spectrum. Completeoxidation to the quaternary salts was observed.

(iii) Calibration Curves

UV study of the compounds prepared in Examples 2-5, 9, 10, 12 and 13revealed that they obey Beer's Law with good coefficients and at a widerange of dilution levels. The study was done at 350 nm for the dihydroderivatives and at 262 and 220 nm for all the quaternary and dihydro.

EXAMPLE 34 Kinetics of Oxidation of the Dihydro Derivatives

In Plasma:

0.2 ml of (6.25×10⁻⁴ M) freshly prepared solution of the dihydroderivative in methyl alcohol was diluted to 10 ml with 20% plasma(diluted whith phosphate buffer pH 7.4). The solution was kept at 37° C.and UV spectrum was scanned from 400 nm to 300 nm every 10 min for 2 hrsagainst reference made by dilution of 0.2 ml methyl alcohol with 20%plasma to 10 ml.

In Whole Blood:

In each of 5 tubes, 0.1 ml of 10×10⁻⁴ M methanolic solution of thefreshly prepared dihydro derivative, was added to 2 ml of freshheparinized whole human blood and the tubes were kept at 37° C. in awater bath. At the end of the time period to be investigated, 8 ml ofacetonitrile was added, and the tubes were shaken vigorously andcentrifuged. The extension of the supernatant solution at 350 nm wasmeasured. A reference sample was made by addition of 0.1 ml of methylalcohol instead of the sample solution following the same procedure.

In Brain Homogenate:

2.0 g of rat brain tissue were homogenized in 10 ml of phosphate buffer,pH 7.4. The homogenate was centrifuged for 15 min at 3000 rpm, decanted,heated in a water bath at 50° C. for 5 min and then centrifuged again.The supernatant solution was diluted to 100 ml with phosphate buffer, pH7.4.

Reference Sample:

0.2 ml of methyl alcohol was diluted to 10 ml with the brain homogenatesolution, and the solution was used to record the base line on a Cary219 spectrophotometer and as a reference for the dihydro derivativesample solution.

Dihydro Derivative Sample Solutions:

0.2 ml of 6.25×10⁻⁴ M methanolic solution of the freshly prepareddihydro derivative was diluted to 10 ml with the brain homogenatesolution. The mixture was scanned at 37° C. from 400 nm to 300 nm every10 min for 2 hrs on a Cary 219 spectrophotometer.

In Liver Homogenate:

Liver Homogenate Solution:

5.0 g of rat liver tissue were homogenized in 50 ml of phosphate buffer,pH 7.4. The homogenate was centrifuged, decanted, heated in a water bathat 50° C. for 5 min and then centrifuged again. The supernatanthomogenate was diluted to 250 ml with phosphate buffer, pH 7.4.

Reference Sample:

0.2 ml of methyl alcohol was diluted to 10 ml with the liver homogenatesolution and the solution was used to record the base line on a Cary 219spectrophotometer and as a reference for the dihydro derivative samplesolution.

Dihydro Derivative Sample Solution:

0.2 ml of 6.25×10⁻⁴ M solution of the freshly prepared dihydroderivative in methyl alcohol was diluted to 10 ml with liver homogenatesolution. The mixture was scanned at 37° C. from 400 nm to 300 nm every5 min for 1 hr.

                                      TABLE II                                    __________________________________________________________________________    Kinetics of Oxidation                                                         Medium K sec.sup.-1                                                                             t1/2 m                                                                             K sec.sup.-1                                                                            t1/2 m                                       __________________________________________________________________________           Comp.                                                                         1-Methyl-3-(N--β-phenethyl)-                                                             1-Benzyl-3-(N--β-phenethyl)-                             carbamoyl-1,4-dihydropyridine                                                                 carbomyl-1,4-dihydropyridine                           Plasma 1.8 × 10.sup.-4                                                                    64.2 7.4 × 10.sup.-5                                                                   156.1                                               n = 13 r = .998 n = 12 r = .998                                        Whole Blood                                                                          8.4 × 10.sup.-4                                                                    13.7 4.7 × 10.sup.-4                                                                   24.4                                                n = 5 r = .952  n = 5 r = .974                                         Brain  4.1 × 10.sup.-4                                                                    28.2 2.1 × 10.sup.-4                                                                   55                                           Homogenate                                                                           n = 8 r = .996  n = 13 r = .999                                        Liver  8.0 × 10.sup.-4                                                                    14.4 7.5 × 10.sup.-4                                                                   15.3                                         Homogenate                                                                           n = 7 r = .999  n = 5 r = .998                                                Comp.                                                                                         5-Carboethoxy-1-methyl-3-(N--β-                          1-Methyl-3,5-di(N--β-phenethyl)-                                                         phenethyl)carbomyl-1,4-dihydro-                               carbamoyl-1,4-dihydropyridine                                                                 pyridine                                               Brain  8.4 × 10.sup.-6                                                                    22.9 1.74 × 10.sup.-5                                                                  11.1                                                                              h                                        Homogenate                                                                           n = 6 r = .997  n = 6 r = .993                                         Whole Blood                                                                          4.9 × 10.sup.-5                                                                    3.9  1.13 × 10.sup.-4                                                                  1.7 h                                               n = 5 r = .949  n = 5 r = .972                                         __________________________________________________________________________

EXAMPLE 35 In Vivo Study in1-Methyl-3-(N-β-phenethyl)carbamoyl-1,4-dihydropyridine

A group of rats of average weight (about 350 g) was injected through thejugular with a solution of the freshly prepared dihydro derivative inDMSO (0.05 g/ml solution) in a dose level of 125 mg/kg animal bodyweight. After the appropriate time period, 1 ml of blood was withdrawnfrom the heart and the animal was perfused with 20 ml of salinesolution. The animal was decapitated. The brains were weighed, kept inthe refrigerator overnight and homogenized in 2 ml of water.Acetonitrile, 8 ml, was added and the mixture was homogenized again andthen centrifuged. The amount of the quaternary was determined from theHPLC spectrum in relation to a recovery experiment made by adding aspecific amount of the quaternary to a blank brain and hybrid in thesame manner of homogenization and extraction.

Brain Results:

    ______________________________________                                              Normalized value                                                              amt in mg/weight lb      Normalized                                     t     in grams          t      value                                          ______________________________________                                         5    .055               40    .1132                                           5    .0423              47    .125                                           10    .099               66    .148                                           15    .0553              90    .1626                                          15    .100               90    .1294                                          20    .0935             145    .0949                                          21    .0743             180    .0838                                          25    .101              185    .1001                                          30    .1242             210    .0707                                          32    .095              220    .0753                                          33    .0778                                                                   ______________________________________                                    

Blood Concentration:

The blood withdrawn was left in the refrigerator overnight and 3 ml ofsaline was added and the mixture shaken, then 17 ml of acetonitrile wasadded and the mixture was shaken vigorously for 1 min and thencentrifuged. The supernatant solution was injected directly into theHPLC.

    ______________________________________                                        Results:                                                                              t (m)                                                                              mg/ml                                                            ______________________________________                                                25   .0235                                                                    40   .0117                                                                    21   .0205                                                                    33   .0058                                                                     5   .0294                                                                    75   .0058                                                                    40   .0088                                                                    15   .0235                                                            ______________________________________                                    

EXAMPLE 36 Kinetics of Disappearance of the Quaternary from BrainHomogenate

A fresh perfused rat brain was homogenized in 20 ml of phosphate buffer,pH 7.4. A solution of 10.0 mg of1-methyl-3-(N-β-phenethyl)carbamoylpyridinium iodide in 2 ml aqueousmethanol (1:1) was added and the thoroughly mixed mixture was kept at37° C. in a water-bath. At each time period, 1 ml of the mixture wastaken and shaken thoroughly with 8 ml of acetonitrile, centrifuged andinjected to HPLC. The amount of the quaternary in the same wasdetermined in comparison with a sample taken at time 0. Linearregression of t against log C shows that K=4.8×10⁻⁵ sec⁻¹, t1/2=3.50 h(in vivo exp.) which was found to be K=8.45×10⁻⁵ sec⁻¹, t1/2=2.1 h,r=0.957.

Studies of the Dopamine Derivatives EXAMPLE 37

Analytical Methods:

A high pressure liquid chromatography (HPLC) method was developed forthe studies of the degradation of the dihydropyridine dopaminederivative. The chromatographic analysis was performed on a componentsystem consisting of a Waters Associate Model 6000A solvent deliverysystem, Model U6K injector and Model 440 dual channel absorbancedetector operated at 254 and 280 nm. A 30 cm×3.9 mm (internal diameter)reverse phase μBondapak C₁₈ column (Waters Associates), operated atambient temperature, was used for all separations. The mobile phase usedfor the separation of the dihydropyridine derivative, its degradationproducts and oxidation products consisted of 0.005M solution of1-heptanesulfonic acid sodium salt (PIC B-7 Eastman Kodak) in CH₃ CN;0.01M aqueous dibasic ammonium phosphate (2.5:1). At a flow rate of 2.0ml/min, 6a had a retention time for 5.1 min; 6c, 11.8 min, 5a, 1.7 min;5c, 3.1 min. A peak was always shown at a retention time of 2.2 minwhich is believed to be a monodeacylated dihydropyridine derivative,since it eventually did result in 6a.

EXAMPLE 38 Determination of the Enzymatic Hydolytic Cleavage and Rate ofOxidation of Compound 5c

In Human Plasma:

The freshly collected plasma used was obtained at the Civitan RegionalBlood Center, Inc. (Gainesville, Fla.) and contained about 80% plasmadiluted with anticoagulant citrate phosphate dextrose solution U.S.P.The plasma was stored in a refrigerator and used the next day. Onehundred μl of a freshly prepared 0.61M solution of compound 5c inmethanol was added to 20 ml of plasma, previously equilibrated to 37° C.in a water bath and mixed thoroughly to result in an initialconcentration of 3.05×10⁻³ moles/liter. One ml samples of plasma werewithdrawn from the test medium, added immediately to 5 ml of ice coldacetonitrile, shaken vigorously and placed in a freezer. When allsamples had been collected, they were centrifuged and the supernatantswere filtered through Whatman 1 filter papers and analyzed by HPLC.

In Human Blood:

The freshly collected heparinized blood was obtained at the CivitanRegional Blood Center, Inc. (Gainesville, Fla.). The blood was stored ina refrigerator and used the next day. One hundred μl of a freshlyprepared 0.19 solution of compound 5c in methanol was added to 20 ml ofblood, previously equilibrated to 37° C. in a water bath and mixedthoroughly to result in an initial concentration of 9×10⁻⁴ moles/liter.One ml samples of blood were withdrawn from the test medium every 5minutes, added immediately to 5 ml of ice cold acetonitrile, shakenvigorously and placed in a freezer. When all samples had been collected,they were centrifuged and the supernatants were filtered using Whatman 4filter paper and analyzed by HPLC.

In Rat Brain Homogenate:

The brain homogenate was prepared by the following method. FiveSprague-Dawley rats were killed by decapitation and the brains wereremoved, weighed (total weight 9.85 g) and homogenized in 49.3 ml ofaqueous 0.11M phosphate buffer, pH 7.4. The homogenate was centrifugedand the supernatant was used for the test. 100 μl of 0.18M solution ofcompound 5c was mixed with 10 ml of homogenate, previously equilibratedto 37° C. in a water bath, to result in an initial concentration of1.8×10⁻³ moles/liter. Samples of 1.0 ml were withdrawn every 10 minutesfrom the test medium, added immediately to 5 ml of ice cold acetonitrileand placed in a freezer. When all samples had been collected, they werecentrifuged. Each supernatant was filtered through two Whatman 1 filterpapers and analyzed by HPLC.

In Rat Liver Homogenate:

The liver homogenate was prepared by the following method. ThreeSprague-Dawley rats were killed by decapitation and the livers wereremoved, weighed and homogenized by tissue homogenizer in 0.11M aqueousphosphate buffer,pH 7.4, to make 20% liver homogenate. The homogenatewas centrifuged and the supernatant was used for the test. 100 μl of0.1M solution of compound 5c in methanol were mixed with 20 ml of thehomogenate, previously equilibrated to 37° C. in a water bath, to resultin an initial concentration of 9×10⁻⁴ moles/liter. Samples of 1.0 mlwere withdrawn every 5 minutes from the test medium, added immediatelyto 5 ml of ice cold acetonitrile, shaken vigorously and placed in afreezer. When all samples had been collected, they were centrifuged andeach supernatant was filtered through Whatman 1 filter paper andanalyzed by HPLC.

Rates of disappearance (overall oxidation and degradation) of compound5c:

    ______________________________________                                        (i)  in Plasma:         R = 2.25 × 10.sup.-4 sec.sup.-1                                         t1/2 = 51.3 min                                                               r = 0.998                                                                     n = (3 × 6)                                     (ii) In 20% Brain Homogenate:                                                                         R = 6.7 × 10.sup.-4 sec.sup.-1                                          t1/2 = 17.2 min                                                               r = 0.996                                                                     n = (3 × 6)                                     (iii)                                                                              In Blood:          R = 6.3 × 10.sup.-4                                                     t1/2 = 18.2 min                                                               r = 0.997                                                                     n = (3 × 7)                                     (iv) In Liver:          R = 1.93 × 10.sup.-3                                                    t1/2 = 5.9 min                                                                r = 0.950                                                                     n = (3 × 5)                                     ______________________________________                                    

EXAMPLE 39 Determination of Concentration of Compound 6a in Brain andBlood after Parenteral Administration of 5c

Male Sprague-Dawley rats of average weight of 150±10 g were used. Therats were anesthetized with IM injection of Inovar and the jugular wasexposed. Compound 5c was injected intrajugularly in the form of 10%solution in DMSO at a dose of 64.2 mg/kg (equivalent to 50 mg/kgcompound 6a). The injection was given at a rate of 24 μl/min using acalibrated infusion pump. After appropriate time periods, 1 ml of bloodwas withdrawn from the heart and dropped immediately into a tared tubecontaining 3 ml acetonitrile, which was afterwards weighed to determinethe weight of the blood taken. The animal was then perfused with 20 mlof saline solution, decapitated and the brain was removed. The weighedbrain was homogenized with 0.5 ml of distilled water, 3 ml ofacetonitrile was added and the mixture was rehomogenized thoroughly,centrifuged, filtered and then analyzed for compound 6a using the HPLCmethod. The tubes containing the blood were shaken vigorously,centrifuged, decanted and also analyzed for compound 6a using the HPLCmethod. Quantitation was done by using a recovery standard curveobtained by introducing a known amount of 6a in either brain homogenateor blood and then treated in the same manner. See FIG. 6 and thediscussion thereof hereinabove.

EXAMPLE 40

Pharmacological studies:

In vivo effect on pituitary prolactin secretion:

Adult male rats (Charles Rivers, CD-1) weighing 200 to 225 g wereprovided food and water ad libitum for at least one week period toexperimentation. To elevate serum prolactin levels, each rat received asingle s.c. implant of a Silastic tube (1.57 mm interior diameter, 5mm×3.15 mm overall size) packed with crystalline 17-β-estradiol. Twodays later the rats were lightly anesthetized with ether and a smallincision was made over the right jugular vein for intravenous (I.V.)administration of the test drugs. Compound 6a was injected at a dose of1 mg/kg body weight/ml saline and groups of six rats were decapitated at15, 30, 60 and 120 min later to collect blood samples. Control rats(time 0) received an I.V. injection of the saline vehicle and weredecapitated 30 min later. Compound 5c was dissolved in 10% ethanol insilane and was injected IV. Rats were decapitated at 15, 30 and 120 minlater. Control (time 0) animals received the 10% ethanol vehicle andwere sampled 30 min later.

Trunk blood was collected, allowed to clot for 2 h and the serum wasseparated and stored at -20° C. for subsequent assay for prolactinconcentrations. Each serum sample was assayed in duplicate by thedouble-antibody radioimmunoassay procedure described by the NationalPituitary Agency Hormone Distribution Program. Serum prolactinconcentrations are expressed in terms of the PRL-RP-2 referencepreparation provided. The intraassay coefficient of variation for 10replicate samples of pooled serum obtained from male rats was 13.8%.

The effects of compounds 5c and 6a on serum prolactin concentrationswere evaluated by one-way analysis of variance and Student-Newman Keulstests. A probability level of less than 0.05 was selected forsignificance. See FIG. 7 and the discussion thereof hereinabove.

The foregoing procedure was repeated, except for the following changes:

Compound 5c (the dihydropyridine dipivalyl ester derivative of dopamine)was dissolved in 10% dimethylsulfoxide in saline and administeredintravenously at a dosage of 1 mg/kg to groups of five or six rats; therats were decapitated at 1, 2, 4, 8, 12 and 24 hours followingadministration. Compound 5a (the dihydropyridine dihydroxy derivative)was dissolved in 10% dimethylsulfoxide and administered intravenously ata dosage of 1 mg/kg to groups of six rats; the rats were decapitated at1, 2 and 4 hours after administration. Control groups of animalsreceived 10% dimethylsulfoxide in saline and were sacrificed 2 hourslater. Intravenous administration of 5c was found to maintain a dramaticreduction in serum prolactin concentrations for at least 12 hoursfollowing adinistration. Again, the rapid onset and very prolongedinhibitory effects of 5c on prolactin secretion is consistent with thetime course of the appearance of 6a in the brain followingadministration of 5c and the "trapping" of 6a in the brain. Compound 5adid produce a significant reduction in serum prolactin concentration at2 hours, but by 4 hours the prolactin levels had increasedsubstantially; thus 5a did not show as prolonged an inhibitory effect asthat exhibited by 5c.

In vitro evaluation of the prolactin inhibitory effect of 6a:

Adult female rats (Charles Rivers Lab.) weighing 225-250 g weremaintained on food and water ad libitum. Animals were sacrificed bydecapitation; their pituitary glands were quickly removed from thecranium. The anterior pituitary (AP) of each animal was dissected intotwo equal halves and placed into incubation media. (Gibco's MinimalEssential Media supplied by Grand Island Biological Co. was used.) Theincubation was conducted at 37° C., under continuous aeration (95% O₂,5% CO₂); the pH was 7.2. After one hour of preincubation, the media werediscarded and replaced with fresh ones containing either DA (2×10⁻⁸ M),6a (2×10⁻⁸) or ascorbic acid (10⁻⁴ M). In all cases, one-half of APreceived the test drug; the other, the ascorbate control. After onehour, samples were taken from the media and the remaining media werediscarded. Fresh media containing DA (2×10⁻⁷), 6a (2×10⁻⁷) andascorbate, respectively, were then added. One hour later, the secondsamples were taken. After the 3 h incubation period, each half AP's wereweighed.

The samples were diluted 1:50 with phosphate buffered saline and thenassayed in triplicate by the radioimmunoassay method described. The dataare given as ng prolactin released/mg wet weight/h. Paired Student'sT-test was used to evaluate the significance of the inhibitory effectsof the test drugs on prolactin secretion. The control AP half and thedrug treated half were employed in each pair comparison. See TABLE I andthe discussion thereof hereinabove.

Further in vitro evaluation of the prolactin inhibitor effect of 6a vs.dopamine:

Eighteen female rats (Charles River Lab.) weighing 225-250 g weremaintained on food and water ad libitum for one week. Animals weresacrificed by decapitation, the pituitary gland was removed from thecranium and the anterior pituitary (AP) was separated from the posteriorand intermediate lobes. The AP was discussed into two equal halves andeach half was placed in an incubation media consisting of Gibco'sMinimal Essential Media containing 25 mM Hepes Buffer (Grand IslandBiological Company, Grand Island, N.Y.). The media was maintained at apH of 7.2 under continuous aeration (95% O₂, 5% CO₂) at a temperature of37° C. Following a one hour preincubation period, the media werediscarded and replaced with fresh media containing either DA (10⁻⁶ M) or6a (10⁻⁶ M). The control AP half received media containing 10⁻⁴ Mascorbic acid, the vehicle for the drugs. After one hour, the media weresampled and the remaining media were discarded. Fresh media containingDA (10⁻⁵ M) or 6a (10⁻⁵ M) or ascorbic acid (10⁻⁴ M) were then added tothe AP halves. One hour later, second samples were taken and the APhalves were weighed to the nearest tenth of a milligram.

Samples of media were diluted 1:50 with phosphate buffered saline andthen assayed in triplicate by radioimmunoassay methods. Data areexpressed as ng prolactin released/mg net weight/h. Pair student's "t"tests were used to evaluate the significance of the effects of the drugson the prolactin release rate. The control AP half and its respectivedrug-treated AP half were employed in each paired comparison. Theresults are tabulated below:

    __________________________________________________________________________    Prolactin ng/mg/h                                                             Dopamine (DA)       6a                                                             DA        DA        6a        6a                                         Control                                                                            (10.sup.-6 M)                                                                      Control                                                                            (10.sup.-5 M)                                                                      Control                                                                            (10.sup.-6 M)                                                                      Control                                                                            (10.sup.-5 M)                              __________________________________________________________________________    306 ± 50                                                                        128 ± 22                                                                        219 ± 26                                                                        59 ± 20                                                                         349 ± 49                                                                        301 ± 51                                                                        205 ± 25                                                                        206 ± 28                                __________________________________________________________________________

Thus, control AP halves released prolactin at a rate of 300 to 350 ng/mgwet weight/h during the first incubation period and about 200 ng/mg wetweight/h during the second incubation period. Dopamine (DA)concentration of 10⁻⁶ and 10⁻⁵ M caused a 58 and 73% decrease inprolactin secretion, respectively. In contrast,N-methylnicotinoyldopamine 6a did not alter the rate of prolactinsecretion at concentrations of 10⁻⁶ or 10⁻⁵ M. These results confirm theconclusions drawn from the earlier studies which were done at lowerconcentrations.

In the examples immediately to follow, all melting points were taken ona Mel-Temp apparatus and are not corrected. Elemental analyses wereperformed at Atlantic Microlab, Inc., Atlanta, Ga. Infrared spectra weredetermined by using a Beckman Acculab 1 double-beam recordingspectrophotometer. NMR spectra were determined by means of Varian T60Aor FX100 spectrometers. All chemical shifts reported are in δ units(parts per million) relative to tetramethylsilane. Ultravioletabsorbance spectra were determined using a Cary Model 210spectrophotometer. HPLC analyses were performed on a Beckman 345 ternaryliquid chromatograph with Model 112 solvent delivery system, Model 210injector, Model 160 absorbance detector and Model 421 controller.

EXAMPLE 41 Preparation of Testosterone nicotinate (compound 41)

Thionyl chloride (2 ml) was added to 0.7 g (5.7 mmol) of nicotinic acidand the mixture was refluxed for 3 hrs. Excess thionyl chloride wasremoved under reduced pressure. To the cold residue, 10 ml of drypyridine was added, followed with 1.44 g (5.0 mmol) of testosterone. Themixture was heated with continuous stirring at 100° C. over a watch bathfor 4 hrs. Pyridine was removed in vacuo and 5 ml of methanol was addedto the oily residue. The mixture was cooled and the solid thatcrystallized was filtered and recrystallized from methanol/acetonemixture to give 1.4 g of 41 as white crystals (yield 71%), m.p.187°-188° C. This intermediate was used directly for the synthesis ofthe chemical delivery system.

EXAMPLE 42 Preparation of17β-[(1-Methyl-3-pyridiniumcarbonyl)oxy]androst-4-en-3-one iodide(compound 42) (Testosterone-17-nicotinate N-methyl iodide)

To a solution of 1.0 g (2.5 mmol) of testosterone nicotinate 41 in 15 mlof acetone, 1 ml of methyl iodide was added and the mixture was refluxedovernight. The yellow solid that separated was removed by filtration,washed with acetone and crystallized from methanol/ether to yield 1.25 g(92% yield) of pure 42 as yellow crystals, m.p. 215°-220° C. (dec.).U.V. (CH₃ OH) λ 270 nm (shoulder) ε=4579; 240 (shoulder), ε=19375. NMR(CDCl₃) δ10.0-8.3 (ms, 4H, pyridinium protons), 5.73 (s, 1H, C₄testosterone proton), 4.86 (s, 3H, ⁺ N--CH₃), 2.40-1.06 (ms, 26H,testosterone skeleton protons). Analysis calculated for C₂₆ H₃₄ INO₃ :C, 58.32; H, 6.40; N, 2.62. Found: C, 58.17; H, 6.48; N, 2.60.

EXAMPLE 43 Preparation of17β-[(1,4-Dihydro-1-methyl-3-pyridinylcarbonyl)oxy]androst-4-en-3-one(compound 43)

To an ice cold solution of 1.1 g (2 mmol) of testosterone nicotinateN-methyl iodide 42 in 150 ml of deaerated 10% aqueous methanol, 0.67 g(8 mmol) of sodium bicarbonate and 1.37 g (8 mmol) of sodium dithionitewere added. The mixture was stirred for 20 minutes and the pale yellowsolid which separated was filtered, washed with water and dried over P₂O₅ under vacuum. Wt. 0.82 g (98% yield), m.p. 172°-175° C. UV (CH₃ OH) λ356 nm, ε=9511; ir (KBr) 1700, 1660 cm⁻¹ (two C═O stretching). NMR (d₆-DMSO) δ 6.90 (bs, 1H, C₂ dihydropyridine proton), 5.83-5.70 (m, 1H, C₆dihydropyridine proton), 5.56 (s, 1H, C₄ testosterone proton), 4.7-4.33(m, 1H, C₅ dihydropyridine proton), 3.26 (bs, 2H, C₄ dihydropyridineprotons), 2.93 (s, 3H, N--CH₃), 2.5-0.83 (m, 26H, testosterone skeletonprotons with the angular methyl protons at 1.16 and 0.83). Analysiscalculated for C₂₆ H₃₅ NO₃ : C, 76.25; H, 8.61; N, 3.42. Found: C,76.07; H, 8.65; N, 3.38.

EXAMPLE 44 Analytical Methods

A high pressure liquid chromatograph (HPLC) method was developed for thestudies of the degradation of the quaternary 42 and dihydropyridinederivative 43. The chromatographic analyses were performed on theBeckman described hereinabove. The absorbance detector was operated at254 nm. A 15 cm×4.6 mm (internal diameter), 5 μm particle sizeultrasphere reverse phase C₁₈ column (Altex), operated at ambienttemperature, was used for all separations. The mobile phase used for theseparation of the dihydropyridine derivative, its degradation productsand oxidation products consisted of 0.002M solution of 1-heptanesulfonicacid sodium salt (PIC B-7 Eastman Kodak) in CH₃ CN, 0.01M aqueousdibasic ammonium phosphate (7:3). At a flow rate of 2.0 ml/min, compound42 had a retention time of 12 min and compound 43, 5 min. For theanalysis of testosterone in the in vivo brain delivery studies, asolvent system consisted of 0.002M solution of PIC B-7 in CH₃ CN, 0.1Maqueous dibasic ammonium phosphate (1:1). At a flow rate of 2.0 ml/min,testosterone had a retention of 3.3 min and compound 42 had a retentiontime of 36.5 min (very broad peak).

EXAMPLE 45 Chemical Oxidation Studies

(i) By Silver Nitrate: 1 ml of 5% methanolic solution of thedihydropyridine compound 43 was added to 5 ml of saturated methanolicAgNO₃ solution. The mixture was shaken, left 10 minutes for completeoxidation, centrifuged and the UV spectrum checked.

(ii) By Hydrogen Peroxide: To a standardized solution of H₂ O₂ (0.18M)contained in a UV cuvette equilibrated at 37° C., a solution ofdihydropyridine compound 43 was added to the sample cuvette to make aconcentration of approximately 5×10⁻⁶ M. The mixture was thoroughlymixed and monitored for the disappearance of the dihydropyridine maximumat 356 nm using a Cary 210 interfaced with an Apple II microprocessorand using an enzyme kinetic software package.

(iii) By Diphenylpicrylhydrazyl Free Radical: To 2 ml of 9.3×10⁻⁵ Msolution of 2,2-diphenyl-1-picrylhydrazyl free radical in acetonitrile,equilibrated at 26° C., 20 ml of 1.5×10⁻² M solution of thedihydropydine compound 43 in acetonitrile was added to make a finalconcentration of 1.48×10⁻⁴ M. The mixture was monitored at 515 nmagainst a reference cuvette containing the same mixture in exactly thesame concentrations, but previously prepared and left for at least 10minutes and used as reference for A∞. The instrument used was a Cary 210interfaced with an Apple II microprocessor and using an enzyme kineticsoftware package.

EXAMPLE 46 Determination of In Vitro Rates of Oxidation of Compound 43in Biological Media

In Human Plasma:

The freshly collected plasma used was obtained at the Civitan RegionalBlood Center, Inc. (Gainesville, Fla.) and contained about 80% plasmadiluted with anticoagulant citrate phosphate dextrose solution U.S.P.The plasma was stored in a refrigerator and used the next day. 100 μl ofa freshly prepared 0.024M solution of compound 43 in DMSO were added to10 ml plasma, previously equilibrated at 37° C. in a water bath andmixed thoroughly to result in an initial concentration of 2.4×10⁻⁴moles/liter. One ml samples of plasma were withdrawn every 20 minutesfrom the test medium, added immediately to 5 ml of ice coldacetonitrile, shaken vigorously and placed in a freezer. When allsamples had been collected, they were centrifuged and the supernatantswere filtered through nitrocellulose membrane filters (por 0.45) andanalyzed by HPLC, following appearance of 42 (Method A).

In Human Blood:

The freshly collected heparinized blood was obtained at the CivitanRegional Blood Center, Inc. (Gainesville, Fla.). The blood was stored ina refrigerator and used the next day. 100 μl of a freshly prepared0.048M solution of compound 43 in DMSO were added to 20 ml blood,previously equilibrated to 37° C. in a water bath and mixed thoroughly,to result in an initial concentration of 2.4×10⁻⁴ moles/liter. One mlsamples of blood were withdrawn from the test medium every 10 minutes,added immediately to 5 ml of ice cold acetonitrile, shaken vigorouslyand placed in a freezer. When all samples had been collected, they werecentrifuged and the supernatants were filtered using nitrocellulosemembrane filters (por 0.45) and analyzed by HPLC, following appearanceof 42 and disappearance of 43.

In Rat Brain Homogenate:

The brain homogenate was prepared by the following method. Five femaleSprague-Dawley rats were killed by decapitation and the brains wereremoved, pooled, weighed (total weight 9.2 g) and homgenized in 36.8 mlof aqueous 0.11M phosphate buffer, pH 7.4. 100 μl of 0.024M solution ofcompound 43 in DMSO were mixed with 20 ml of the homogenate, previouslyequilibrated to 37° C. in a water bath, to result in an initialconcentration of 2.4×10⁻⁴ moles/liter. Samples of 1.0 ml were withdrawnevery 10 minutes from the test medium, added immediately to 5 ml of icecold acetonitrile, shaken vigorously and placed in a freezer. When allsamples had been collected, they were centrifuged and the supernatantswere filtered through nitrocellulose membrane filter (por 0.45) andanalyzed by HPLC (Method A).

EXAMPLE 47 In Vitro Determination of the Site-Specific Conversion of theProdrug 42 to Testosterone

A fresh brain homogenate was prepared as above described. 100 μl of0.017M solution of the quaternary compound 42 in methanol were mixedwith 10 ml of the brain homogenate, previously equilibrated to 37° C. toresult in an initial concentration of 1.7×10⁻⁴ M. Samples of 1.0 ml werewithdrawn every 20 minutes from the test medium, added immediately to 5ml of ice cold acetonitrile and placed in a freezer. When all thesamples had been collected they were centrifuged and the supernatant wasfiltered through nitrocellulose membrane filter (por 0.45) and analyzedfor the quaternary compound 42.

EXAMPLE 48 In Vivo Brain Delivery of Testosterone FollowingAdministration of the Dihydro Compound 43

Female Sprague-Dawley rats of average weight of 225±10 g were used. Therats were anesthetized with IM injection of Innovar^(R) (0.13 ml/kg) andthe external jugular was exposed. Compound 43 was injectedintrajugularly in the form of 2.5% solution in DMSO at a dose of 40mg/kg (equivalent to 52.3 mg quaternary 42 or 28.2 mg testosterone). Theinjection was given at a rate of 44.4 μl/minute using a calibratedinfusion pump. After appropriate time periods, 1 ml of blood waswithdrawn from the heart and dropped immediately into a tared tubecontaining 5 ml acetonitrile which was later weighed to determine theweight of the blood taken. The animal was then perfused with 20 ml ofsaline solution, decapitated and the brain was removed. The weighedbrain was homogenized with 1 ml of distilled water, 5 ml of acetonitrilewas added and the mixture was rehomogenized thoroughly, centrifuged,filtered and then analyzed using the HPLC method. The tubes containingthe blood were shaken vigorously, centrifuged, filtered and alsoanalyzed using the HPLC method described at 0.05 sensitivity limit fordetermination of the quaternary 42 and at 0.001 sensitivity limit fordetermination of liberated testosterone. Quantitation was done using arecovery standard curve obtained by introducing a known amount of eithercompound 42 or testosterone in either brain homogenate or blood and thentreating in the same manner of extraction and analysis.

EXAMPLE 49 In Vivo Brain Delivery of Testosterone Following itsAdministration

Female Sprague-Dawley rats with an average weight of 225±10 g wereinjected with testosterone at a dose level of 28.2 mg/kg following thesame procedure previously described. Samples of brain and bloodcollected were analyzed for testosterone using HPLC.

EXAMPLE 50 In Vivo Brain Delivery of Quaternary 42 Following itsAdministration

Following the same procedure, female Sprague-Dawley rats were injectedI.V. with the quaternary solution (0.18%) in DMSO at a dose level of13.0 mg/kg (it was found to be toxic at higher doses). The brain samplescollected were analyzed for presence of the quaternary 42 using HPLC.

EXAMPLE 51 Results of Experiments of Examples 45-50

The rates of oxidation of the dihydro derivative 43 with silver nitrate,hydrogen peroxide and diphenylpicrylhydrazyl free radical (DPP.) weredetermined. The reactions were carried out under pseudo first orderconditions, either with higher concentrations of the oxidant in the caseof hydrogen peroxide or higher concentrations of 43 in the case of thepicryl reagent. With DPP., a reference sample was made using the sameamounts as the test sample, but prepared 10 minutes before mixing andmonitoring the test sample. This reference is used as a measure of A∞and these were the data used to calculate the kinetic parameters. The invitro rates of oxidation of the dihydro derivative were also determinedin biological fluids, e.g. 80% plasma, whole blood, 20% brain homogenateand 20% liver homogenate. The rate of disappearance of the ester 42 andappearance of testosterone in the medium was also determined. Finally,the in vivo brain delivery and blood concentration profile of thequaternary derivative and testosterone released, against time, wasdetermined following a single injection of the dihydropyridinederivative 43 to female rats. These results were compared to blood andbrain kinetics of testosterone following administration of such.

Chemical Oxidation of the Dihydropyridine Derivative 43

(i) By Silver Nitrate:

It was observed that this dihydro derivative 43 is more stable towardsoxidation than the monophenethylamine type derivatives reportedhereinabove; it takes a few minutes' standing for the silver to form.The product is exclusively the quaternary salt 42, as verified by thechange in the UV and NMR spectra.

(ii) By Hydrogen Peroxide:

At low concentrations of the dihydro compound 43 (5×10⁻⁶ M), compared tothe high concentration of the peroxide (0.18M), the oxidation proceedsaccording to a first order kinetics. k=2.7±0.3×10⁻³ sec⁻¹ t_(1/2)=3.98±0.7 min r=0.995 At higher concentrations, the dihydro compound isinsoluble in H₂ O₂.

(iii) By Diphenylpicrylhydrazyl (DPP.) Free Radical:

The reaction was carried out under pseudo first order conditions usingexcess of the dihydropyridine derivative. With the concentrations used,all runs gave good first order plots over 3 half lives, with correlationcoefficient better than 0.9998. k=4.87±31×10⁻² sec⁻¹ t_(1/2) =14.1±0.6seconds Trials to determine the second order rate constant usingdifferent concentrations of DPP. were unsuccessful.

(iv) In Vitro Oxidation and Hydrolysis in Biological Media:

Table III shows the rates, half-lives and correlation coefficient forthe process of oxidation of the 1,4-dihydropyridine derivative 43 indifferent biological media.

The rate of hydrolysis of the quaternary 42 in 20% brain homogenate wasalso determined and it was found to be 3.6×10⁻⁵ sec⁻¹, corresponding toa half-life, t_(1/2), of 5:16 h.

                  TABLE III                                                       ______________________________________                                        Kinetics of in vitro oxidation                                                of the dihydropyridine ester 43 to the                                        quaternary derivative 42 in biological fluids..sup.a                                                   t1/2                                                 Medium        k(sec.sup.-1)                                                                            (min.)  r    Method.sup.b                            ______________________________________                                        80% Plasma    8.12 × 10.sup.-5                                                                   142     .959 A                                       20% Brain Homogenate                                                                        1.72 × 10.sup.-4                                                                   67      .997 A                                       Whole Blood   1.74 × 10.sup.-4                                                                   66      .997 A,B                                     ______________________________________                                         .sup.a At 37° C., initial concentration of [43] = 2.4 ×          10.sup.-4 M                                                                   .sup.b Method A: Following appearance of                                      Method B: Following disappearance of [43                                 

(v) In Vivo Administration of Compound 43 and Testosterone:

FIG. 8 illustrates the concentration of the quaternary derivative 42 inbrain and blood and concentration of testosterone released in the brain,following intravenous administration of the 1,4-dihydropyridinederivative 43. Also, FIG. 8 shows the concentration of testosterone inbrain and blood following administration of testosterone. Statisticalanalysis of the descending portions of the curves shown in FIG. 8provides the following results:

    ______________________________________                                        (1) Rates of disappearance of the quaternary compound 42:                     from brain = 2 × 10.sup.-3 min.sup.-1                                                       t.sub.1/2  = 5.7 hr r = .833                              from blood = 1.27 × 10.sup.-2 min.sup.-1                                                    t.sub.1/2  = 54 min r = .833                              (2) Rate of disappearance of released testosterone                            following administration of dihydro compound 43 =                             2.65 × 10.sup.-3 min.sup.-1                                                            t.sub.1/2  = 4.4 h                                                                          r = .768                                         (Results analyzed for up to 5 hrs, the data shown                             in FIG. 8 are for 3 hrs)                                                      (3) Rate of disappearance of testosterone following                           administration of testosterone:                                               from brain = 5.5 × 10.sup.-2 min.sup.-1                                                     t.sub.1/2  = 12.6 min r = .994                            from blood = 4.74 × 10.sup.-2 min.sup.-1                                                    t.sub.1/2  = 14.5 min r = .959                            ______________________________________                                    

Thus,17β-[(1,4-dihydro-1-methyl-3-pyridinylcarbonyl)oxy]androst-4-en-3-one 43could be obtained in a high yield (more than 90%) from testosterone17β-nicotinate by simple chemical procedures. The dihydro productobtained directly from the reduction reaction medium was found by HPLCto be quite pure and a single crystallization from hot methanol affordedan analytically pure product. No signs of oxidation were observed duringcrystallization, even from hot methanol, filtration or drying. Thecrystalline solid dihydro compound did not show signs of oxidation,decomposition or polymerization when tested by HPLC, during the 2-monthshelf storage at ambient temperature under nitrogen. This compound 43was found to be quantitatively oxidizable to the correspondingquaternary derivative 42, as identified by UV spectroscopy, whether bysilver nitrate or hydrogen peroxide. The process of oxidation withsilver nitrate is slower than that with the dihydropyridine derivativeof phenethylamine reported hereinbelow. Oxidation with hydrogen peroxideor DPP., at pseudo first order conditions, was found to take place atmeasurable rates (t_(1/2) =3.98±0.7 min and 14.1±0.6 seconds,respectively) compared to the rates of oxidation of the correspondingphenethylamine and dopamine derivatives which were found to be too fastto be monitored using the same procedure. The in vitro investigation inbiological fluids indicated a facile oxidative conversion of the dihydroform 43 to the corresponding quaternary 42, but at a slower rate thanthat of the analogous amides of phenethylamine or dopamine.

Insofar as concerns the in vivo studies of compound 43, the resultsshown in FIG. 8 indicate that the dihydro derivative penetrates the BBBand is readily oxidized in the brain to the quaternary precursor 42. Thein vivo rate of oxidation of the dihydro seems faster than that obtainedfrom the in vitro experiment. No dihydro derivative could be detected inthe brain without the sensitivity limits of the procedure. After 42reaches its maximum concentration, within about 15 minutes, itsconcentration starts a decline phase corresponding to overall excretionand/or metabolismhydrolysis. The overall rate of this phase wascalculated to be 2×10⁻³ min⁻¹ (t_(1/2) =5.7 h). In the same time, theconcentration of 42 in blood was decreasing progressively from thebeginning at a rate 1.27×10⁻² min⁻¹ or with a half life of 54 min.Equimolar administration of testosterone using the same solvent (DMSO)and the same route of administration showed a rapid absorption oftestosterone into the brain, reaching a maximum concentration within 5minutes, followed by fast clearance from both brain and blood (t_(1/2)=12.6 min and 14.5 min respectively). The ratio of brain/bloodconcentration for testosterone was found to be 1.6 at 5 minutes and 1.8at 15 minutes from administration. The ratio of brain/bloodconcentration of the quaternary 42 was found to increase progressivelywith time (3.23 at 15 min, 6.33 at 45 min and 12 at 3 hrs fromadministration). This indicates the predicted "lock in" property for thequaternary 42. Testosterone was found to be released from the quaternaryester 42 and could be detected in the brain following administration ofthe dihydro derivative 42. Analysis of the time concentration curve forrelease of testosterone indicated two phase kinetics for disappearancefrom the brain. The first phase is a fast descending one at a rate of1.2×10⁻² min⁻¹ followed by a slow clearance phase with a rate of5.8×10⁻⁴ min⁻¹ and a half life of about 20 hrs which corresponds toabout 130 hrs for complete clearance from the brain. This result, ifcompared to that obtained by H. Frey, A. Aadvaag, D. Saahum and J.Falch, Eur. J. Clin. Pharmacol., 16, 345 (1979), for the clearance oftestosterone from plasma after oral administration (about 6 hrs), isvery promising. Although the concentrations of testosterone in the brainfollowing administration of compound 43 are low compared to thatfollowing administration of testosterone, this is by no means adisadvantage because such high concentration of testosterone may not beneeded for receptor saturation. By dose manipulation of the dihydroderivative, a concentration of testosterone just sufficient for receptorsaturation for a delayed period could be attained.

In the examples immediately to follow, all melting points were taken ona Mel-Temp apparatus and are not corrected. Elemental analyses wereperformed at Atlantic Microlabs, Inc., Atlanta, Ga. Infrared spectrawere determined by means of a Beckman Acculab 1 double-beam recordingspectrophotometer. NMR spectra were determined by means of a Varian T60Aspectrometer. All chemical shifts reported are in δ (parts per million)relative to tetramethylsilane. Ultraviolet absorbance spectra weredetermined using a Carey Model 219 spectrophotometer. HPLC analyses wereperformed on a Waters Associates Liquid chromatograph with Model 6000Asolvent delivery system, Model U6K injector and Model 440 absorbancedetector.

EXAMPLE 52 Preparation of the 1-Methyl-3-carbamoylpyridinium derivativeof Tyr-Gly-Gly-Phe-Leu-OC₂ H₅ (1-Methyl-3-carbamoylpyridinium derivativeof leu⁵ -enkephalin ethyl ester)

N-α-t-Butoxycarbonyl-O-benzyl-L-tyrosine (7 g, 0.019 mol) was dissolvedin tetrahydrofuran in a three-neck round bottom flask which was cooledto approximately -10° C. in an ice/acetone bath under a nitrogenatmosphere. N-methylmorpholine (6.3 ml, 0.06 mol) was added to thestirred solution, followed by 2.5 ml (0.019 mol) of isobutylchloroformate. Immediately after the addition of isobutyl chloroformate,N-methyl morpholine hydrochloride precipitated. After 5 min, 3.7 g(0.019 mol) of L-leucine ethyl ester hydrochloride, dissolved indimethylformamide, were added. The reaction mixture was stirred at thistemperature for an hour, after which the solvent was evaporated. Theresidue obtained was dissolved in ethyl acetate/water and the organiclayer was extracted with sodium bicarbonate solution, water, 0.01N HCland water. The organic layer was dried over Na₂ SO₄ and afterevaporation of the solvent an oil was obtained. Crystallization fromCHCl₃ /petroleum ether yielded 7.4 g (0.014 mol, 76%) m.p. 104°-107° C.,of N-α-t-butoxycarbonyl-O-benzyl-L-tyrosylglycylglycine ethyl ester. ¹ HNMR (CDCl₃) δ 7.2 (5H, s), 6.9 (4H, doublet of doublets), 5.0 (2H, s),1.1 (12H, m). The ethyl ester was cleaved by treating 6.2 g (0.012 mol)of it with an equivalent amount of 2N NaOH in methanol. The solution wasstirred at room temperature for half an hour after which the solvent wasevaporated. An equivalent amount of 2N HCl was added to the cooledresidue and the solid obtained was filtered and dried to yield 3.5 g(96%), m.p. 118°-122° C., of the free(t-butoxycarbonyl-O-benzyl)tyrosylglycylglycine.t-Butoxycarbonylphenylalanylleucine ethyl ester was prepared startingwith 6 g (0.019 mol) of t-butoxycarbonyl-L-phenylalanine, and 3.7 g(0.019 mol) of leucine ethyl ester hydrochloride. Work up andcrystallization from CHCl₃ /petroleum ether yielded 6.5 g (84%), m.p.109°-112° C., of the desired compound. ¹ H NMR (CDCl₃) δ 7.2 (5H, s),6.4 (1H bm), 5.1 (1H, bm), 4.3 (4H, bm), 3.1 (2H, bm), 1.3 (20H, m).

The t-butoxycarbonyl protecting group was cleaved by treatment of 4.9 g(0.012 mol) of t-butoxycarbonylphenylalanylleucine ethyl ester with 60ml of 33% trifluoroacetic acid/CH₂ Cl₂. The solution was stirred at roomtemperature for half an hour, after which the solvent was evaporated andthe residue was treated with a bicarbonate solution which resulted inthe formation of a solid. The solid, phenylalanylleucine ethyl ester,was filtered, rinsed with water and dried to yield 5.6 g (97%), m.p.150°-154° C.

t-Butoxycarbonyl-O-benzyltyrosylglycylglycylphenylalanylleucine ethylester was prepared by the same method using 0.1 mol of startingmaterials, (t-butoxycarbonyl-O-benzyl)tyrosylglycylglycine andphenylalanylleucine ethyl ester. A white solid was obtained which wasrecrystallized from methyl alcohol/water to yield 4.9 g (63%), m.p.149°-152° C.

The t-butoxycarbonyl group oft-butoxycarbonyl-O-benzyltyrosylglycylglycylphenylalanylleucine ethylester was cleaved as previously described to giveO-benzyl-tyr-gly-gly-phe-leu-OEt.TFA (trifluoroacetic acid) salt. Anal.calc. of C₃₉ H₄₈ O₉ N₅ F₃.H₂ O: C, 58.13; H, 6.25; N, 8.69. Found: C,58.06; H, 6.26; N, 8.69).

Nicotinic acid (160 mg, 1.3 mmole) andO-benzyl-tyr-gly-gly-phe-leu-OEt.TFA salt (1 g, 1.3 mmole) weredissolved in pyridine and 268 mg (1.3 mmole) of dicyclohexylcarbodiimidewere added. The mixture was stirred at room temperature for 24 hrs,after which the dicyclohexylurea was filtered and the pyridine distilledin vacuo. Water was added to the residue and the solid obtained wasfiltered and washed with more water. The solidN-nicotinoyl-O-benzylpentapeptide ethyl ester was recrystallized bymethanol/water. ¹ H NMR gave the expected pattern.

The N-nicotinoyl pentapeptide derivative (500 mg, 0.64 mmol) obtainedabove was dissolved in 10% formic acid/methanol, followed by addition of500 mg of palladium black. The mixture was stirred overnight at roomtemperature, after which the solvent was evaporated. The residue wasneutralized with a saturated NaHCO₃ solution and extracted with ethylacetate. The solvent was evaporated and the residue recrystallized fromethyl acetate/ethyl ether to yield 370 mg (0.54 mmol), 84% of product. ¹H NMR gave the expected pattern, corresponding to ##STR1540## Anal.calc. for C₃₆ H₄₄ O₈ N₆.4H₂ O: C, 56.83; H, 6.89; N, 11.04. Found: C,56.88; H, 6.56; N, 10.48. That product (30 mg, 0.44 mmol) was dissolvedin acetone and an excess of methyl iodide was added. The solution wasrefluxed for 8 hrs, after which the solvent was evaporated and theresidue was filtered from ethyl ether. A yellowish (260 mg, 0.31 mm),71%, product was obtained, corresponding to the1-methyl-3-carbamoylpyridinium derivative of leu⁵ -enkephalin ethylester. Anal. calc. for C₃₇ H₄₇ O₈ N₆ I: C, 53.50; H, 5.70; N, 10.12.Found: C, 53.44; H, 4.77; N, 10.07.

EXAMPLE 53 Preparation of N[2-(3-Indolyl)ethyl]nicotinamide

To a solution of 1.97 g (10 mmol) of tryptamine hydrochloride and 1.23 g(10 mmol) of nicotinic acid in 10 ml of dry pyridine at 0° C. were added2.20 g (10.7 mmol) of dicyclohexylcarbodiimide. The reaction mixture wasstirred at room temperature for 24 hrs, and the formed dicyclohexylureawas removed by filtration (2.34 g). The pyridine was removed in vacuo,and 10 ml of methanol were added to the residue. Insolubledicyclohexylurea in methanol was removed by filtration (0.05 g). Themethanol was removed in vacuo and 10 ml of methylene chloride was addedto the residue. Insoluble compound in methylene chloride was removed byfiltration (0.04 g). The methylene chloride was removed in vacuo and theresidue was crystallized from isopropanol. Recrystallization frommethanol/isopropanol gave 1.92 g (72.5%) ofN-[2-(3-indolyl)ethyl]nicotinamide as pale brown plates, m.p. 150°-152°C. IR (KBr) 3280, 3050, 2940, 1646, 1526, 1412, 1302, 1102, 740, 697cm⁻¹. Anal. calc. for C₁₆ H₁₅ N₃ O: C, 72.42; H, 5.91; N, 15.84. Found:C, 72.51; H, 5.74; N, 15.77.

EXAMPLE 54 Preparation of1-Methyl-3-{[N-2-(3-indolyl)ethyl]}carbamoylpyridinium iodide

To a solution of 1.06 g (4 mmol) of N-[2-(3-indolyl)ethyl]nicotinamidein 5 ml of methanol, 1 ml (16 mmol) of methyl iodide was added. Themixture was refluxed for 5 hrs. The methanol and excess methyl iodidewere removed in vacuo. The residue was recrystallized frommethanol/isopropanol to yield 1.42 g (87.4%) of1-methyl-3{[N-2-(3-indolyl)ethyl]}carbamoyl pyridinium iodide as yellowneedles, m.p. 215°-217° C. IR (KBr): 3280, 3000, 2940, 1660, 1540, 1500,1316, 1220, 735 cm⁻¹. Anal. calc. for C₁₇ H₁₈ N₃ OI: C, 50.13; H, 4.46;N, 10.32; I, 31.16. Found: C, 50.22; H, 4.49; N, 10.27; I, 31.06. Theproduct has the structural formula: ##STR1541##

EXAMPLE 55 Preparation of1-Methyl-3-{N-[2-(3-indolyl)ethyl]}carbamoyl-1,4-dihydropyridine

To a solution of 0.61 g (1.5 mmol) of1-methyl-3{[N-2-(3-indolyl)ethyl]}carbamoylpyridinium iodide in 50 ml ofdeaerated water and 50 ml of ethyl acetate, 1.00 g (12 mmol) of sodiumbicarbonate was added. The mixture was stirred in an ice bath and 1.65 g(8 mmol) of sodium dithionite was added gradually under nitrogen. Themixture was stirred for 6 hrs, the ethyl acetate layer was decanted andthe water layer was extracted with ethyl acetate. The combined solutionwas washed with water, dried with anhydrous sodium sulfate and thesolvent removed in vacuo. A yield of1-methyl-3{N-[2-(3-indolyl)ethyl]}carbamoyl-1,4-dihydropyridine of 0.29g (69%) was obtained as a yellow semisolid, m.p. 40°-70° C. IR (KBr)3250, 2900, 1670 cm⁻¹. Anal. calc. for C₁₇ H₁₉ N₃ O.1/2H₂ O: C, 70.32;H, 6.94; N, 14.47. Found: C, 70.47; H, 6.76; N, 14.52. The product hasthe structural formula: ##STR1542##

EXAMPLE 56 Preparation of 5-Benzyloxygramine

A solution of 8.90 g (0.04 mol) of 5-benzyloxyindole in 40 ml of dioxanewas added dropwise, over the course of 30 mins, to an ice-cooled,stirred mixture of 40 ml of dioxane, 40 ml of acetic acid, 3.2 ml of 37%aqueous formaldehyde (0.04 mol) and 8.8 ml of 25% aqueous dimethylamine(0.05 mol). The solution was stirred and cooled for two hrs and thenallowed to warm to room temperature overnight. The next day, 500 ml ofwater were added, and the turbid mixture which resulted was filteredafter the addition of charcoal. The filtrate was made alkaline (to pH8-9) with 400 ml of 10% sodium hydroxide solution. The gramine quicklysolidified and was filtered off after cooling in the refrigeratorovernight. Washing with water, and drying gave 9.20 g (82.0%) of coarsepowder, m.p. 125°-128° C. Recrystallization from ethyl acetate gaveslightly green glittering cubes, m.p. 136°-137° C., of the desired5-benzyloxygramine. IR (KBr) 3110, 3020, 2920, 2840, 2800, 2755, 1610,1575, 1470, 1455, 1480, 1210, 1190, 1000 and 780 cm⁻¹.

EXAMPLE 57 Preparation of 5-Benzyloxyindole-3-acetamide

A solution of 8.41 g (0.03 mol) of 5-benzyloxygramine, 7.5 g (0.15 mol)of sodium cyanide, 120 ml of ethanol and 30 ml of water was refluxed for90 hours. The solution, which contained some precipitate, was dilutedwith 200 ml of water and cooled in the refrigerator. The crystallinematerial which separated was washed thoroughly with water and dried,giving 4.40 g (52.3%) of a slightly brown sticky tan powder, m.p.137°-140° C. Recrystallization from methanol/benzene gave small needles,m.p. 156°-158° C., of 5-benzyloxyindole-3-acetamide. IR (KB) 3400, 3290,3180, 1645, 1610, 1580, 1485, 1450, 1275, 1210, 1200 and 795 cm⁻¹.

EXAMPLE 58 Preparation of 5-Benzyloxytryptamine hydrochloride

4.21 (0.015 mol) of 5-benzyloxyindole-3-acetamide which were dissolvedin 200 ml of tetrahydrofuran were added gradually to a solution of 3.80g (0.1 mol) of lithium aluminum hydride in 200 ml of ether over a 30minute period and under a nitrogen atmosphere. The solution was refluxedfor 24 hrs. The excess hydride was decomposed with ethanol and thenwater was added to ensure complete decomposition of the precipitatedcomplex. The ether layer was decanted and the residue was washed withfresh ether. The combined solution was washed with water and dried oversolid potassium hydroxide. The solvent was evaporated in vacuo and theoily residue was taken up in ether and precipitated with hydrogenchloride gas. The pale purple 5-benzyloxytryptamine hydrochloride wasrecrystallized from ethanol/ether, yield 3.00 g (66.0%), m.p. 263°-265°C. IR (KBr) 3290, 3010, 2910, 1600, 1580, 1480, 1200, 1100 and 1000cm⁻¹.

EXAMPLE 59 Preparation ofN-{2-[3-(5-benzyloxy)indolyl]ethyl}nicotinamide

To a solution of 303 mg (1 mmol) of 5-benzyloxytryptamine hydrochlorideand 123 mg (1 mmol) of nicotinic acid in 5 ml of pyridine at 0° C. wasadded 220 mg (1.07 mmol) of dicyclohexylcarbodiimide. The reactionmixture was stirred at room temperature for 24 hrs and the formeddicyclohexylurea was removed by filtration. The pyridine was removed invacuo, and the residue was recrystallized from methanol/isopropanol.Yield 218 mg (58.9%), m.p. 192°-194° C. ofN-{2-[3-(5-benzyloxy)indolyl]ethyl}nicotinamide. IR (KBr) 3280, 3050,2900, 1655, 1590, 1535, 1480, 1310, 1220, 1200, 1185, 1020, and 710cm⁻¹.

EXAMPLE 60 Preparation of1-Methyl-3-N-{2-[3-(5benzyloxy)indolyl]ethyl}carbamoylpyridinium iodide

To a solution of 185 mg (0.5 mmol) ofN-{2-[3-(5-benzyloxy)indolyl]ethyl}nicotinamide in 2 ml of methanolthere was added 0.2 ml (3.2 mmol) of methyl iodide. The mixture wasrefluxed for 3 hrs. The methanol and excess methyl iodode were removedin vacuo. The residue of yellow solid gradually turned purplish. Yield128 mg (50.0%), m.p. 228°-230° C., IR (KBr) 3210, 3020, 1670, 1495,1480, 1190, 1025, 1000, 770 cm⁻¹. The product has the formula##STR1543##

Catatylic hydrogenolysis, using palladium-on-charcoal catalyst, of1-methyl-3-N-{2-[3-(5-benzyloxy)indolyl]ethyl}carbamoylpyridinium iodideaffords 1-methyl-3-N-{2-[3-(5-hydroxy)indolyl]ethyl}carbamoylpyridiniumiodide. Subsequent esterification with trimethylacetyl chloride affordsthe corresponding pivalyl ester of the formula ##STR1544## which canthen be reduced as described hereinabove to the corresponding dihydroderivative of the formula ##STR1545##

EXAMPLE 61 Peparation of1-Methyl-3-{{N-{1-ethoxycarbonyl-2-[4-bis(2-chloroethyl)aminophenyl]}ethyl}}carbamoylpyridine

Melphalan ethyl ester hydrochloride (153 mg, 0.41 mmol) was dissolved inacetonitrile (5 ml). A mixture of dicyclohexylcarbodiimide (89 mg, 0.43mmol) and nicotinic acid (50.9 mg, 0.41 mmol) in acetonitrile (1 ml) andpyridine (1 ml) was added to the stirred solution of hydrochloride at 0°C. After approximately 5 minutes, the clear mixture became cloudy. Themixture was allowed to warm to room temperature and stirred for 44 hr,after which time the precipitate was removed by filtration. Solventswere removed at reduced pressure to give an orange oil which was takeninto chloroform (15 ml) and washed with cold water (5 ml). Removal ofsolvent in vacuo gave 90 mg of a soft yellow solid (50% yield) which wasused without further purification in the following step. δ(CDCl₃): 9.3(bs, 1H, pyridine H-2); 8.9-9.2 (m, 1H, pyridine H-4); 7.9-8.2 (m, 1H,pyridine H-6); 7.5 (m, 1H, pyridine H-5); 6.95 (AB_(q), 4-H); 4.9-5.3(m, 1H, C--H; 4.3 (q, 2H, OCH₂); 3.5-3.9 [bs, 8H, (CH₂ CH₂)₂ ]; 3.2(dist. d, 2H, ArCH₂); 1.3 (t, 3H, CH₃). The product has the formula:##STR1546##

EXAMPLE 62 Preparation of1-Methyl-3-{{N-{1-ethoxycarbonyl-2-[4-bis(2-chloroethyl)aminophenyl]}ethyl}}carbamoylpyridiniumiodide

The product of Example 61 (76.5 mg, 0.173 mmol) in acetone (10 ml) wastreated with methyl iodide (0.1 ml, 1 mmol) and the mixture was heatedat gentle reflux; further methyl iodide (0.1 ml) was added after 4hours. Thin layer chromatography (CHCl₃ :methanol, 10:1) showed severalspots, including a quaternary compound at the origin. No further changein TLC was apparent after 6 hours, at which time heat was removed andsolvents were evaporated in vacuo to leave a red-orange oil (118 mg).The oil was dissolved in d₆ acetone and insoluble particles were removedby filtration through a cotton plug. δ[(CD₃)₂ CO] 9.7 (bs, 1H, pyridineH-2); 8.9-9.5 (m, 2-H, pyridine H-4, H-6); 8.1-8.4 (m, 1H, pyridineH-5); 4.8-5.1 (m, 1H, CH); 4.7 (s, 3H, N⁺ CH₃); 4.2 (q, 2H, OCH₂); 3.75[bs, 8H, (CH₂ CH₂)₂ ]; 3.2 (s, HOD+ArCH₂); 1.25 (5, 3H, CH₃). Theproduct is further characterized by the structural formula: ##STR1547##

EXAMPLE 63 Preparation of1-Methyl-3-{{N-{1-ethoxycarbonyl-2-[4-bis(2-chloroethyl)aminophenyl]}ethyl}}carbamoyl-1,4-dihydropyridine

The product of Example 62 (101 mg, 0.174 mol) and sodium bicarbonate(5.8 mg, 6.8 mmol), as a suspension in ice cold N₂ deaerated water (15ml) and methanol (2 ml), were treated with sodium dithionite (91 mg, 5.2mmol) and ethyl acetate (20 ml). The original pale yellow suspensionbecame yellow instantly, and after 2 hours the mixture was clear.Aqueous and organic layers were separated and the aqueous layer wasextracted with ethyl acetate (4×20 ml). The combined organic layers weredried over sodium sulfate at 0° C. in the dark. Removal of solvent invacuo gave a yellow-orange oil which reduced methanolic AgNO₃ : yield 77mg, 97%, δ(CDCl₃) 6.5-5.9 (bd, 1H, pyridine H-6); 4.5-5.1 (m, 2H,pyridine 4-5+C--H); 4.2 (q, 2H, OCH₂); 3.75 [bs, 8H, (CH₂ CH₂ )₂ ];3.05-3.3 [m, 4H, CH₂ Ar+pyridine H-4 (CH₂)]; 3.0 (s, 3H, NCH₃); 1.3 (t,3H, CH₃). λmax (methanol) 356.5 nm. The product has the formula:##STR1548##

EXAMPLE 64 Preparation of 3-Nicotinoyloxyestra-1,3,5(10)-trien-17-one(Estrone Nicotinate)

To nicotinic acid (41 g, 0.333 mol) at 0° C. was added thionyl chloride(115 ml, 1.58 mol) with stirring. The mixture was refluxed for one hour,and the white crystalline product was filtered and washed sparingly withdry benzene. Excess thionyl chloride was azeotroped off with dry benzeneimmediately before use. Yield 90% (53.97 g) of nicotinoyl chloridehydrochloride; NMR, IR identical with literature values.

To nicotinoyl chloride hydrochloride (2.65 g, 0.015 mol) in pyridine (20ml) at 0° C. was added estrone (2 g, 0.0074 mol). The mixture wasrefluxed for one hour and then poured over 100 ml of ice cold water,filtered, and dried over P₂ O₅ under vacuum. Yield 72% (2.0076 g), m.p.207°-210° C. NMR (CDCl₃) δ9.3-9.1 (br s, 1H, C₂ pyridinium proton),8.8-8.6 (br d, 1H, C₆ pyridinium proton, 8.4-8.2 (br d, 1H, C₄pyridinium proton), 7.5-7.1 (m, 2-H, C₅ pyridinium proton+C₁ estroneproton), 7.0-6.7 (m, 2H, C₂,4 estrone protons), 3.2-1.3 (estroneskeletal protons, 15), 1.0-0.9 (s, 3H, C₁₈ estrone protons). IR (KBr)1750-1730 cm⁻¹ (broad C═O stretching). Anal. calculated for C₂₄ H₂₅ NO₃; C, 76.76; H, 6.72; N, 3.73. Found: C, 76.37; H, 6.96; N, 3.67. Theproduct is further characterized by the structural formula: ##STR1549##

EXAMPLE 65 Preparation of3-[(1-Methyl-3-pyridiniumcarbonyl)oxy]estra-1,3,5(10)-trien-17-oneiodide

To estrone nicotinate (0.5 g, 0.0013 mol) in acetone (20 ml) was addedmethyl iodide (1 ml, 0.016 mol) and the mixture was refluxed overnight.The deep yellow precipitate was filtered, washed with acetone, anddried. Yield 90% (0.6226 g); m.p. 245°-248° C. (dec.). NMR (d₅ -DMSO)δ9.8-9.7 (br s, 1H, C₂ pyridinium proton), 9.4-9.0 (m, 2H, C₄, C₆pyridinium protons), 8.4-8.0 (m, 1H, C₅ pyridinium proton), 7.4-7.2 (m,1H, C₁ estrone proton), 7.1-6.9 (m, 2H, C₂,4 estrone protons), 3.2.1.3(estrone skeletal protons, 15), 1.0-0.9 (s, 3H, C₁₈ estrone protons). IR(KBr) 1755-1740 (broad C═O stretching). Anal. calculated for C₂₅ H₂₈ NO₃I: C, 58.03; H, 5.47; N, 2.71. Found: C, 58.16; H, 5.51; N, 2.67. Theproduct has the formula: ##STR1550##

EXAMPLE 66 Preparation of3-[(1-Methyl-1,4-dihydro-3-pyridinylcarbonyl)oxy]estra-1,3,5(10)-trien-17-one

To 3-[(1-methyl-3-pyridiniumcarbonyl)oxy]estra-1,3,5(10)-trien-17-oneiodide (0.600 g, 1.16 mmol) in a 50:50 mixture of methanol and deaeratedwater (80 ml) were added NaHCO₃ (0.58 g, 7.0 mmol) and Na₂ S₂ O₄ (0.81g, 4.6 mmol). The mixture was stirred under N₂ for 2 hours. Theprecipitate was filtered, dissolved in methanol at room temperature,filtered, and then reprecipitated with deaerated water. This precipitatewas then filtered and dried over P₂ O₅ under vacuum. Yield 67% (0.3029g). The product decomposes over the range 130°-180° C. NMR (CDCl)δ7.2-7.0 (m, 2H, C₁ estrone protons+C₂ dihydro proton), 6.8-6.6 (m, 2H,C₂,4 estrone protons), 5.8-5.3 (m, 1H, C₆ dihydro proton), 5.0-4.6 (m,1H, C₅ dihydro proton), 3.2-3.0 (m, 2H, C₄ dihydro protons), 3.0-2.8 (s,3H, N--CH₃), 2.5-1.2 (estrone skeletal protons, 15), 1.0-0.9 (s, 3H, C₁₈estrone protons). IR (KBr) 1745-1740 (C═O stretching). Anal. calculatedfor C₂₅ H₂₉ NO₃ (+1/2H₂ O): C, 74.96; H, 7.56; , N 3.50. Found: C,75.44; H, 7.27; N, 3.38. The product is further characterized by thestructural formula: ##STR1551##

EXAMPLE 67 Preparation of 17β-Nicotinoyloxyestra-1,3,5(10)-trien-3-ol3-methyl ether

To nicotinoyl chloride hydrochloride (3.15 g, 0.017 mol) in pyridine (20ml) at 0° C. was added estradiol 3-methyl ether (2 g, 0.0070 mol). Afterrefluxing one hour, the mixture was poured over 100 ml of ice water,filtered and dried over P₂ O₅ under vacuum. Yield 76% (2.0674 g), m.p.140°-142° C. NMR (CDCl₃) δ9.3-9.0 (br s, 1H, C₂ pyridinium proton,8.8-8.6 (m, 1H, C₆ pyridinium proton), 8.4-8.1 (br d, 1H, C₄ pyridiniumproton), 7.5-7.0 (m, 2H, C₅ pyridinium proton+C₁ estradiol proton),6.8-6.5 (m, 2H, C₂,4 estradiol protons), 5.1-4.7 (m, 1H, C₁₇α estradiolproton), 3.8-3.6 (s, 3H, O--CH₃), 3.0-1.2 (15H, estradiol skeletalprotons), 1.0-0.9 (s, 3H, C₁₈ estradiol protons). IR (KBr) 1725 (C═Ostretching). Anal. calculated for C₂₅ H₂₉ NO₃ : C, 76.68; H, 7.48; N,3.58. Found: C, 76.49; H, 7.50; N, 3.55. The product has the formula:##STR1552##

EXAMPLE 68 Preparation of17β-[(1-Methyl-3-pyridiniumcarbonyl)oxy]estra-1,3,5(10)-trien-3-ol3-methyl ether iodide

To 17β-nicotinoyloxyestra-1,3,5(10)-trien-3-ol 3-methyl ether (1.5 g,0.0038 mol) in acetone (20 ml) was added methyl iodide (1 ml, 0.016 mol)and the mixture was refluxed overnight. The pale yellow precipitate wasfiltered, washed with acetone, and dried. Yield 76% (1.5595 g), m.p.230°-234° C. (dec.). NMR (d₆ -DMSO) δ9.5-9.3 (br s, 1H, C₂ pyridiniumproton), 9.2-8.8 (m, 2H, C₄,6 pyridinium protons), 8.3-8.0 (m, 1H, C₅pyridinium proton), 7.2-7.0 (m, 1H, C₁ estradiol proton), 6.8-6.5 (m,2H, C₂,4 estradiol protons); 5.2-4.8 (m, 1H, C₁₇α estradiol proton),4.6-4.4 (s, 3H, N--CH₃), 3.8-3.6 (s, 3H,O--CH₃), 3.0-1.2 (15H, estradiolskeletal protons), 1.0-0.9 (s, 3H, C₁₈ estradiol protons). IR (KBr) 1745(C═O stretching). Anal. calculated for C₂₆ H₃₂ NO₃ I: C, 58.53; H, 6.06;N, 2.63. Found: C, 58.25; H, 6.07; N, 2.59. The title compound has theformula: ##STR1553##

EXAMPLE 69 Preparation of17β-[(1-Methyl-1,4-dihydro-3-pyridinylcarbonyl)oxy]estra-1,3,5(10)-trien-3-ol3-methyl ether

To 17β-[(1-methyl-3-pyridiniumcarbonyl)oxy]estra-1,3,5(10)-trien-3-ol3methyl ether (0.600 g, 1.12 mmol) in a 50:50 mixture of methanol anddeaerated water (80 ml) were added NaHCO₃ (0.57 g, 6.7 mmol) and Na₂ S₂O₄ (0.78 g, 4.5 mmol). The mixture was stirred under N₂ for 2 hours. Theprecipitate was filtered, dissolved in methanol at room temperature,filtered, and then reprecipitated with deaerated water. This precipitatewas then filtered and dried over P₂ O₅ under vacuum. Yield 74% (0.3383g). The product decomposes over the range 120°-170° C. NMR (CDCl₃)δ7.3-7.2 (m, 1H, C₁ estradiol proton), 7.0-6.9 (s, 1H, C₂ dihydroproton), 6.8-6.6 (m, 2H, C₂,4 estradiol protons), 5.8-5.6 (m, 1H, C₆dihydro proton), 5.0- 4.6 (m, 2H, C₅ dihydro proton+C₁₇α estradiolproton), 3.9-3.7 (s, 3H, O--CH₃), 3.2-3.0 (m, 2H, C₄ dihydro protons),3.0-2.8 (s, 3H, N--CH₃), 2.4-1.2 (15H, estradiol skeletal protons),1.0-0.9 (s, 3H, C₁₈ estradiol protons). IR (KBr) 1705 (C═O stretching).Anal. calculated for C₂₆ H₃₃ NO₃ : C, 76.61; H, 8.18; N, 3.44. Found: C,76.75; H, 8.43; N, 3.37. The product is further characterized by thestructural formula: ##STR1554##

EXAMPLE 70 Preparation of Estra-1,3,5(10-triene-3,17β-diol3,17-dinicotinate (Estradio 3,17β-dinicotinate)

Estradiol (2 g, 0.0073 mol) was added to nicotinoyl chloridehydrochloride (5.3 g, 0.029 mol) in dry pyridine (30 ml) at 0° C. Themixture was refluxed for 1 hour and then poured over 100 ml of icewater, filtered and dried over P₂ O₅ under vacuum. Yield 90% (3.18 g),m.p. 148°-150° C. NMR (CDCl₃) δ9.2-9.0 (br s, 2H, C₂ pyridiniumprotons), 8.7-8.3 (m, 2H, C₆ pyridinium protons), 8.4-8.0 (m, 2H, C₄pyridinium protons), 7.5-7.1 (m, 3H, C₅ pyridinium protons+C₁ estradiolproton), 6.9-6.7 (m, 2H, C₂,4 estradiol protons), 5.0-4.7 (m, 1H, C₁₇αestradiol proton), 3.2-1.3 (estradiol skeletal protons, 15), 1.0-0.9 (s,3H, C₁₈ estradiol protons). Ir (KBr) 1750, 1725 cm⁻¹ (2 C═O stretching).Anal. calculated for C₃₀ H₃₁ N₂ O₄ : C, 74.50; H, 6.47; N, 5.79. Found:C, 74.40; H 6.32; N, 5.75. The product has the formula: ##STR1555##

EXAMPLE 71 Preparation of3,17β-Bis[(1-methyl-3-pyridiniumcarbonyl)oxy]estra-1,3,5(10)-trienediiodide

Methyl iodide (1 ml, 0.016 mol) was added to estradiol3,17β-dinicotinate (1 g, 0.0021 mol) in acetone (20 ml) and the mixturewas refluxed overnight. The deep yellow precipitate which formed wasfiltered, washed with acetone, and dried. Yield 72% (1.262 g), m.p.256°-258° C. (dec.). NMR (d₆ -DMSO) δ9.6-9.2 (br s, 2H, C₂ pyridiniumprotons), 9.2-8.7 (m, 4H, C₄ +C₆ pyridinium protons), 8.4-8.0 (m, 2H, C₅pyridinium protons), 7.3-7.1 (m, 1H, C₁ estradiol proton), 7.1-6.9 (m,C₂,4 estradiol protons), 5.0-4.7 (m, 1H, C₁₇α estradiol proton), 4.5-4.3(s, 6H, N--CH₃), 3.2-1.3 (estradiol skeletal protons, 15), 1.0-0.9 (s,3H, C₁₈ estradiol protons). IR (KBr) 1750-1735 cm⁻¹ (broad C═Ostretching). Anal. Calculated for C₃₂ H₃₆ N₂ O₄ I₂ : (+1 H₂ O): C,48.99; H, 4.89; N, 3.57. Found: C, 48.78; H, 4.66; N, 3.63. The productis further characterized by the structural formula: ##STR1556## Thatcompound was converted to the corresponding 3-hydroxy steroid of theformula ##STR1557## by partial hydrolysis; the resultant 3-hydroxycompound was then reduced, as generally described hereinabove, to affordthe corresponding dihydro derivative of the formula ##STR1558## Whenthat dihydro derivative was administered to male rats, the corresponding3-hydroxy-17-quaternary derivative was found in the brain.

EXAMPLE 72 In Vitro Testing of Estrogenic Steroid Derivatives

The products of Examples 66 and 69 both reduce methanolic silvernitrate. The product of Example 66 requires more time and some warming.

The two above-mentioned dihydro derivatives show disappearance of UVabsorption at 359 and 358 nm, respectively, upon addition of H₂ O₂.Diphenylpicrazyl radical absorption at 516 nm can also be shown todecrease upon addition of ether of these compounds.

Disappearance of the product of Example 66 in brain and plasmahomogenates was studied using the Cary 210 and Apple II microprocessor.

    ______________________________________                                        Brain Homogenate                                                              Concentration                                                                             t1/2 (min.)                                                                              k (sec.sup.-1)                                                                           r                                           ______________________________________                                        2.68 × 10.sup.-4 M                                                                  11.2       1.03 × 10.sup.-3                                                                   0.9998                                      1.18 × 10.sup.-4 M                                                                  8.7        1.33 × 10.sup.-3                                                                   0.9998                                      4.07 × 10.sup.-5 M                                                                  7.5        1.53 × 10.sup.-3                                                                   0.9989                                      ______________________________________                                    

    ______________________________________                                        Plasma Homogenate                                                             Concentration                                                                             t1/2 (min.)                                                                              k (sec.sup.-1)                                                                           r                                           ______________________________________                                        1.43 × 10.sup.-4 M                                                                  39.7       2.97 × 10.sup.-4                                                                   0.992                                       7.04 × 10.sup.-5 M                                                                  52.7       2.19 × 10.sup.-4                                                                   0.969                                       2.75 × 10.sup.-5 M                                                                  66.2       1.75 × 10.sup.-4                                                                   0.953                                       ______________________________________                                    

EXAMPLE 73 Preparation of Estra-1,3,5(10)-triene-3,17β-diol17-nicotinate (Estradiol 17β-nicotinate)

0.5% Potassium bicarbonate in 95% methanol (60 ml) was added toestradiol 3,17β-dinicotinate (0.5 g, 0.0010 mol) and the slurry wasstirred overnight at room temperature. Water (60 ml) was added andrepeated extractions into chloroform were made, combined and dried overanhydrous sodium sulfate. The chloroform was removed in vacuo and theresulting pinkish-white solid was suspended in methanol at roomtemperature. The white powder thus obtained was separated by filtrationand dried. Yield 94% (0.3663 g), m.p. 221°-222° C. Anal. calc. for C₂₄H₂₇ NO₃ : C, 76.36; H, 7.22; N, 3.71. Found: C, 76.20; H, 7.25; N, 3.70.The product has the formula: ##STR1559##

EXAMPLE 74 Preparation of17β-[(1-Methyl-3-pyridinium)carbonyloxy]estra-1,3,5(10)-trien-3-oliodide

Methyl iodide (2 ml, 0.032 mol) was added toestra-1,3,5(10)-triene-3,17β-diol 17-nicotinate (2.0953 g, 0.0056 mol)in acetone (200 ml) and the mixture was refluxed overnight. The paleyellow precipitate which formed was removed by filtration, washed withacetone and dried. Yield 83% (2.4203 g), m.p. 268°-272° C. (dec). Anal.calc. for C₂₅ H₂₉ NO₃ I: C, 57.92; H, 5.65; N, 2.70. Found: C, 57.70; H,5.73; N, 2.68. The product has the formula: ##STR1560##

EXAMPLE 75 Preparation of17β-[(1-Methyl-1,4-dihydro-3-pyridinyl)carbonyloxy]estra-1,3,5(10)-trien-3-ol

To 17β-[(1-methyl-3-pyridinium)carbonyloxy]estra-1,3,5(10)-trien-3-oliodide (1.09 g, 0.0021 mol) in 50:50 t-butanol/deaerated water (150 ml)was added NaHCO₃ (1.06 g, 0.0126 mol) and Na₂ S₂ O₄ (1.46 g, 0.0084mol). The mixture was stirred under N₂ for one hour.

The precipitate which formed was removed by filtration, dissolved inether and dried over anhydrous Na₂ SO₄. The ether was removed in vacuo.Yield 64% (0.2416 g). The product decomposes over the range 115°-130° C.Anal. calc. for C₂₅ H₃₁ NO₃ (+1/2H₂ O): C, 74.59; H, 8.03; N, 3.48.Found: C, 74.57; H, 8.04; N, 3.40. The product is characterized by thestructural formula: ##STR1561##

EXAMPLE 76 Preparation of 17α-Ethynylandrost-4-en-17β-ol-3-one17-nicotinate (Ethisterone nicotinate)

Ethisterone (2.5 g, 8.0 mmol) was dissolved in 100 ml of dry pyridine.Excess nicotinoyl anhydride (2.5 g, 11.0 mmol) and a catalytic amount ofDMAP were added. The solution was stirred for 5 days, then poured intoice water. The resulting white powder was removed by filtration andwashed. Yield 85%, 2.84 g, m.p. 203°-204° C. The product has theformula: ##STR1562##

EXAMPLE 77 Preparation of17α-Ethynyl-17β-[(1-methyl-3-pyridinium)carbonyloxy]androst-4-en-3-oneiodide

Ethisterone nicotinate (1 g, 1.79 mmol) was dissolved in 50 ml ofacetonitrile. Methyl iodide (0.76 g, 5.3 mmol) was added and thesolution was refluxed overnight. The yellow solid thus obtained wasremoved by filtration and washed. Yield 95%, 1.27 g. UV(CH₃ OH) λ_(max)=224 nm. The product has the formula: ##STR1563##

EXAMPLE 78 Preparation of17α-Ethynyl-17β-[(1-methyl-1,4-dihydro-3-pyridinyl)carbonyloxy]androst-4-en-3-one

The product of Example 77 (300 mg) was added to 100 ml of cold degassedwater. Then, 0.135 g of NaHCO₃ and 0.281 g of Na₂ S₂ O₄ were added andthe solution was stirred for 30 minutes, then repeatedly extracted withchloroform. The chloroform layers were combined and dried over MgSO₄.The solvent was removed under reduced pressure, yielding a yellow, highmelting foam. Yield 0.11 g or 47%. UV(CH₃ OH) ν_(max) =240 nm, others208 nm, 362 nm. The compound has the structural formula: ##STR1564##

EXAMPLE 79 Preparation of N-Nicotinoyltyrosine ethyl ester

Nicotinic acid (12.3 g, 0.1 mol) was dissolved in dry pyridine (300 ml).The solution was cooled and dicyclohexylcarbodiimide (20.6 g, 0.1 mol)was added. After dissolution, tyrosine ethyl ester hydrochloride (24.6g, 0.1 mol) was added and the solution was stirred overnight. Theprecipitated dicyclohexylurea (DCU) was removed by filtration.Additional DCU was removed by triturating the oil with hot water. Theproduct was purified with acetone. Calculated for C₁₇ H₁₈ N₂ O₄.1/2H₂ O:C, 63.16; H, 5.88; N, 8.66. Found; C, 63.10; H, 5.96; N, 8.59. Theproduct can also be namedN-[1-ethoxycarbonyl-2-(4'-hydroxyphenyl)ethyl]nicotinamide.

EXAMPLE 80 Preparation of N-[(1-Methyl-3-pyridinium)carbonyl]tyrosineethyl ester iodide

N-Nicotinoyltyrosine ethyl ester (20 g, 0.06 mol) was dissolved in 200ml of acetone. A two molar excess of methyl iodine (25.6 g, 0.18 mol)was added and the mixture was refluxed for 6 hours. The solvent wasremoved under reduced pressure to yield the desired product as a solidfoam. NMR analysis confirmed the identity of the product, which has thestructural formula ##STR1565## and can also be named1-methyl-3-{N-[(1'-ethoxycarbonyl)-2'-(4"-hydroxyphenyl)ethyl}carbamoylpyridiniumiodide.

EXAMPLE 81 Preparation of1-Methyl-3{N-[(1'-ethoxycarbonyl)-2'-(4"-pivaloyloxyphenyl)ethyl]}carbamoylpyridiniumtrifluoroacetate

The product of Example 80 (6 g, 0.013 mol) was dissolved in 50 ml ofcold trifluoroacetic acid at 0° C. in an ice bath. Pivaloyl chloride(3.14 g, 0.026 mol) was slowly added and the solution was warmed to roomtemperature. After 24 hours, the solvent was removed under reducedpressure. The resulting dark oil was triturated with petroleum ether butno solidification occurred. Identity of the product was confirmed by NMRanalysis. The product was dissolved in aqueous methanol (10%) andextracted with ethyl ether to remove a highly colored contaminate beforeusing as the starting material in Example 83 below.

EXAMPLE 82 Preparation of1-methyl-3-{N-[(1'-ethoxycarbonyl)-2'-(4"-isobutyryloxyphenyl)ethyl]}carbamoylpyridiniumtrifluoroacetate

The product of Example 80 (6 g, 0.013 mol) was dissolved in 50 ml oftrifluoroacetic acid cooled to 0° C. in an ice bath. To that solutionwith stirring, was slowly added isobutyryl chloride (2.77 g, 2.76 ml).The solution was stirred overnight at ambient temperature and thesolvent was removed under reduced pressure. The oil was stirredovernight with petroleum ether and then dried in vacuo, but nosolidification occurred. Identity of the product was confirmed by NMRanalysis. The product was dissolved in aqueous methanol (10%) andextracted with ethyl ether to remove a highly colored contaminant beforeusing in Example 84 below.

EXAMPLE 83 Preparation of1-Methyl-3-{N-[(1'-ethoxycarbonyl)-2'-(4"-pivaloyloxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine

The product of Example 81 (4.07 g, 0.0079 mol) was dissolved in 100 mlof 25% aqueous methanol. Nitrogen gas was bubbled through the solution.To the solution, stirring in an ice bath, was then added NaHCO₃ (2.02 g,0.024 mol). Ethyl ether (100 ml) was added, followed by the addition ofNa₂ S₂ O₄ (4.12 g, 0.024 mol). The yellow biphasic solution was stirredfor 30 minutes, then the layers were separated and the aqueous layer wasextracted twice with 75 ml portions of ethyl ether. The combined organicfractions were dried over Na₂ SO₄ and the solvent was removed underreduced pressure to afford a solid foam which oxidized ethanolic silvernitrate. Anal. Calc. for C₂₃ H₂₀ N₂ O₅.1/2H₂ O: C, 65.23; H, 7.33.Found: C, 65.76; H, 7.28; N, 6.95.

EXAMPLE 84 Preparation of1-Methyl-3-{N-[(1'-ethoxycarbonyl)-2'-(4"-isobutyryloxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine

The product of Example 82 (2.20 g, 0.0044 mol) was dissolved in 100 mlof aqueous methanol. The solution was cooled in an ice bath with astream of N₂ passing through it. To this solution, NaHCO₃ (1.11 g,0.0132 mol) and ether (100 ml) were added. Then, sodium dithionite (2.30g, 0.0132 mol) was added and the solution was stirred for 30 minutes.The layers were separated and the aqueous phase was washed with ethylether. The combined organic layers were dried over anhydrous Na₂ SO₄ andreduced in volume. The resultant orange oil oxidized ethanolic silvernitrate. Identity of the product was confirmed by NMR analysis.

EXAMPLE 85 Preparation of1-Methyl-3-{N-[(1'-ethoxycarbonyl)-2'-4"-acetoxyphenyl)ethyl]}carbamoylpyridiniumtrifluoroacetate

The product of Example 80 (4.70 g, 0.01 mol) was dissolved in 30 ml oftrifluoroacetic acid cooled in a water bath. Acetyl chloride (1.56 g,0.02 mol) was added, with stirring. The solution was then stirredovernight. The solvent was removed under reduced pressure and theresulting oil was dissolved in aqueous methanol and extracted with ethylether. The product was obtained as a pale yellow oil. Its identity wasconfirmed by NMR analysis.

EXAMPLE 86 Preparation of1-Methyl-3-{N-[(1'-ethoxycarbonyl)-2'-(4"-acetoxyphenyl)ethyl]}carbamoyl-1,4-dihydropyridine

The product of Example 85 (2.76 g, 5.7 mmol) was dissolved in 25%aqueous methanol. The solution was stirred at 0° C. while adding NaHCO₃(1.44 g, 0.017 mol). A layer of 100 ml of ethyl ether was added,followed by the addition of Na₂ S₂ O₄ (2.98 g, 0.017 mol). The systemwas stirred for 30 minutes, then the layers were separated. The aqueouslayer was extracted with ether (2×50 ml), then the combined organiclayers were extracted with cold degassed water. The ether layer wasdried over Na₂ SO₄ and the solvent was removed under reduced pressure togiven an orange oil. UV (CH₃ OH) 214 nm, 358 nm. Anal. calc. for C₂₀ H₂₄N₂ O₅ O: C, 64.52; H, 6.45; N, 7.53. Found: C, 63.90; H, 6.72; N, 7.70:I, 0.0.

EXAMPLE 87 Preparation of Valproic acid chloride (2-Propylpentanoylchloride)

To 4.32 g (30 mmol) of valproic acid in an ice bath, thionyl chloride(3.60 g, 30 mmol) was slowly added, with stirring. The neat mixture wasallowed to come to room temperature and then heated in a water bath at50° C. for 30 minutes. 50 Ml portions of dry benzene were twice addedand removed under reduced pressure. The resultant product was used insubsequent reactions without further purification.

EXAMPLE 88 Preparation of Valproic acid 2-iodoethyl ester (2'-Iodoethyl2-propylpentanoate)

To the product of Example 87 (4.87 g, 30 mmol), 2-iodoethanol (5.16 g,30 mmol) was added with stirring and cooling in an ice bath. The neatmixture was then heated to 100° C. in a water bath for 10 minutes, thenremoved from the heat and stirred for an additional 10 minutes. Thereaction mixture was then dissolved in 50 ml of ether, washed with water(1×30 ml), 5% NaOH (2×30 ml), and again with water (2×30 ml). The etherlayer was dried over anhydrous sodium sulfate and the solvent wasremoved under reduced pressure. A light yellow liquid product wasobtained in 67% yield from valproic acid (6.0 g). Silver nitrate gave abright yellow precipitate. NMR analysis confirmed the identity of theproduct.

EXAMPLE 89 Preparation of1-[2'-(2"-Propyl)pentanoyloxy]ethyl-3-carbamoylpyridinium iodide

The product of Example 88 (3.28 g, 11 mmol) and 50 ml ofdimethylformamide were added to nicotinamide (1.22 g, 10 mmol). Themixture was heated to reflux for 3 hours, then was cooled. Removal ofsolvent under reduced pressure afforded a brown oily residue, which wasstirred with ether (60 ml) for 30 minutes, giving a yellow powder. Theether was decanted and a fresh portion of ether (50 ml) was added. Thecrude product was vacuum filtered under N₂, then was recrystallized fromisopropanol/ether to give 3.5 g of the desired product (84% yield), m.p.111°-112° C. The product has the formula: ##STR1566##

EXAMPLE 90 Preparation of1-[2'-(2"-Propyl)pentanoyloxy]ethyl-3-carbamoyl-1,4-dihydropyridine

To 50 ml of ice-cold degassed deionized water, the product of Example 89(420 mg, 1 mmol) was added. To that solution, NaHCO₃ (366 mg, 4 mmol)and Na₂ S₂ O₄ (696 mg, 4 mmol) were added, with stirring. Nitrogen gaswas bubbled through the solution for 30 minutes. The aqueous solutionwas then extracted with ether (6×25 ml) until the ether layer was nolonger yellow. The combined ether extracts were washed with water (1×50ml) and dried over MgSO₄. The ether layer was decanted from the dryingagent and the solvent was removed under reduced pressure. To the oilresidue, ether was added and then removed (10×5 ml) on a vacuum pump. Afoam was formed, which returned to an oil upon exposure to theatmosphere. Structure was confirmed by NMR analysis.

EXAMPLE 91 Preparation of2-(3-Pyridyl)carbonylamino-3-(3,4-dihydroxy)phenylpropanoic acid ethylester

L-DOPA ethyl ester (5 g, 17.8 mmol) in dry pyridine (20 ml) was treatedwith a solution containing dicyclohexylcarbodiimide (4 g, 10% excess)and nicotinic acid (2.21 g, 17.8 mmol) in dry pyridine (50 ml) at roomtemperature. The mixture was stirred for 24 hours, after which time theurea which formed was removed by filtration and washed with CH₃ CN.Solvents were removed in vacuo to give an orange, highly hygroscopicfoam. The crude product was taken up in CHCl₃ (100 ml) containing 1 dropof methanol and washed with cold water (50 ml). Drying over MgSO₄ andremoval of solvent in vacuo left an orange foam, which was taken up inCH₃ CN (15 ml). Insoluble material was removed by filtration through aglass wool plug. The filtrate was evaporated to dryness to give ahygroscopic yellow-orange foam which collapsed on exposure to theatmosphere. The product was taken up in CHCl₃ (60 ml) and washed, firstwith 0.5% and then with 0.25% aqueous sodium bicarbonate. Drying overMgSO₄ and evaporation to dryness left an orange foam which did notcollapse on atmospheric exposure. NMR analysis confirmed that theproduct has the structure: ##STR1567##

EXAMPLE 92 Preparation of2-(3-Pyridyl)carbonylamino-3-(3,4-dipivaloyloxy)phenylpropanoic acidethyl ester

The product of Example 91 (250 mg, ˜0.76 mmol) was taken up in CHCl₃ (15ml) and allowed to react with pivaloyl chloride (200 mg, 10% excess) atgentle reflux overnight. Removal of volatiles in vacuo yielded a yellowfoam, which was again treated with CHCl₃. Triethylamine was added untilcomplete solution was obtained, at which point pivaloyl chloride (200mg, 10% excess) was added and the solution was heated at reflux for 4hours, then allowed to cool overnight. Washing with water (50 ml),drying over MgSO₄ and removal of solvent in vacuo gave an off-white foamwhich gave a negative FeCl₃ test, indicating no free phenolic groupsremained. The material was highly hydroscopic. NMR analysis confirmedthe identity of the product.

EXAMPLE 93 Preparation of1-Methyl-3-{N-[1-ethoxycarbonyl-2-(3,4-dihydroxy)phenyl]}carbamoylpyridiniumiodide

The product of Example 91 (250 mg, 0.76 mmol) in CH₃ CN (10 ml) wastreated with methyl iodide (100 mg, 2-fold excess) at room temperature.The solution was stirred overnight, after which time the solvent wasremoved in vacuo to give a yellow foam, m.p. 75°-82° C. NMR analysisconfirmed the identity of the quaternary salt.

EXAMPLE 94 Preparation of1-Methyl-3-{N-[1-ethoxycarbonyl-2-(3,4-dipivaloyloxy)phenyl]}carbamoylpyridiniumiodide

The product of Example 92 (190 mg, 0.38 mmol) in CH₃ CN (10 ml) wastreated with CH₃ I (250 mg, 5 equivalents) and the mixture was heated atgentle reflux, using an ice-cooled condenser. After 4 hours, heating wasdiscontinued and volatiles were removed in vacuo to leave a yellow foam(200 mg, 82%). The material is hygroscopic and melts over a broad range.Testing with methanolic FeCl₃ indicates that no free phenolic OH'sremain. Identity of the product was confirmed by NMR analysis.

EXAMPLE 95 Preparation of1-Methyl-3-{N-[1-ethoxycarbonyl-2-(3,4-dipivaloyloxy)phenyl]}carbamoyl-1,4-dihydropyridine

The product of Example 94 (180 mg, 0.28 mmol) in distilled water (20 ml)and ethanol (1.0 ml) at 0° C. was treated with NaHCO₃ (95 mg, 4equivalents) and Na₂ S₂ O₄ (146 mg, 3 equivalents) under nitrogen. Ethylether (40 ml) was added and the mixture was stirred for 40 minutes. Thenthe organic and aqueous layers were separated and the aqueous layer wasreextracted with ethyl ether (3×20 ml). The combined organic layers weredried (MgSO₄) and the solvent was removed in vacuo to leave an oilyfoam. The product was taken up in a minimum of CHCl₃ and passed down ashort neutral alumina column, using CHCl₃ as eluant. The isolatedmaterial showed NMR and UV spectral properties in accord with theassigned structure: ##STR1568##

EXAMPLE 96 Preparation of 4-Aminobutanoic acid benzyl esterhydrochloride

GABA (4 g, 38.8 mmol) was suspended in 50 ml (0.48 mol) of benzylalcohol. The reaction mixture was stirred, with cooling on an ice bath,while 20 ml SOCl₂ was added dropwise over a 30 minute period. Themixture was slowly brought to the reflux temperature and refluxed for 4hours. The resultant pink viscous solution was cooled to roomtemperature. Addition of 50 ml of ethyl ether and refrigerationovernight produced white crystals which were collected by filtration,recrystallized from a mixture of ethyl ether and ethanol and dried, m.p.115°-116° C.

EXAMPLE 97 Preparation of3-{N-[(3'-benzyloxycarbonyl)propyl]carbamoyl}pyridine

Nicotinic acid (1.07 g, 8.7 mmol) was dissolved in a minimum amount ofdry pyridine. Dicyclohexylcarbodiimide (1.97 g, 9.6 mmol) was dissolvedin the mixture, with stirring. The solution was cooled to 0° C. and4-aminobutanoic acid benzyl ester hydrochloride (2 g, 8.7 mmol) wasadded. After 30 minutes, the solution turned yellow and a precipitatewas observed. Stirring was continued for 48 hours, after which time 1.8g of dicyclohexylurea was removed from the yellow solution byfiltration. The solution was evaporated to dryness and the residue waswashed with 40 ml of ice cold water, extracted into ethyl acetate anddried over Na₂ SO₄. Evaporation of solvent left the desired product as asticky yellow oil. Identity of the product, which has the structuralformula ##STR1569## was confirmed by NMR analysis.

EXAMPLE 98 Preparation of1-Methyl-3-{N-[(3'-benzyloxycarbonyl)propyl]}carbamoylpyridinium iodide

The product of Example 97 (0.92 g, 3.09 mmol) was dissolved in a minimumamount of acetone and cooled to 0° C. Methyl iodide (0.40 ml, 6.4 mmol)was added in one portion and the solution was slowly brought to thereflux temperature. The mixture was refluxed for 3 hours, then stirredovernight. Evaporation of solvent left a yellow oil which crystallizedand which was recrystallized from acetone/ethyl ether. The light yellowcrystals thus obtained were collected by filtration and dried. Anal.calc. for C₁₈ H₂₁ N₂ O₃ I.1/8H₂ O: C, 48.86; H, 4.84; N, 6.33; I, 28.72.Found: C, 48.84; H, 4.81; N, 6.33; I, 28.94. UV (λ_(max))=264, 236 nm.NMR and IR analysis also confirmed the identity of the product.

EXAMPLE 99 Preparation of1-Methyl-3-{N-[(3'-benzyloxycarbonyl)propyl]}carbamoyl-1,4-dihydropyridine

The product of Example 98 (200 mg, 0.45 mmol) was dissolved in 20 mldeaerated water. Sodium bicarbonate (0.23 g, 6-fold excess) was added tothe solution, with stirring. Sodium dithonite (0.31 g) was added and ayellow color was observed. Ethyl acetate (30 ml) was added and themixture was stirred for 11/2 hours. The organic layer, containing theyellow dihydro compound, was separated from the aqueous layer and driedover Na₂ SO₄. Evaporation of ethyl aetate left a yellow oil whichreduced methanolic silver nitrate immediately. UV and NMR analysisconfirmed the identity of the product, which has the formula ##STR1570##

EXAMPLE 100 Preparation of 4-Aminobutanoic acid cyclohexyl esterhydrochloride

GABA (8 g, 77.6 mmol) was suspended in 100 ml (0.96 mol) ofcyclohexanol. Thionyl chloride (40 ml) was added dropwise to the mixtureat 0° C. The mixture was then refluxed for 4 hours, cooled andcrystallized from ethyl ether. The white crystals obtained in thismanner were filtered and dried. NMR analysis confirmed the identity ofthe product.

EXAMPLE 101 Preparation of3-{N-[(3'-Cyclohexyloxycarbonyl)propyl]}carbamoylpyridine

Nicotinic acid (2.2 g, 18 mmol) was suspended in 50 ml of dry pyridine.Dicyclohexylcarbodiimide (3.68 g, 17.9 mmol) was dissolved in thesolution, with stirring. 4-Aminobutanoic acid cyclohexyl esterhydrochloride (4 g, 18 mmol) was added and the mixture was stirred for48 hours. Precipitated dicyclohexylurea was removed by filtration andthe filtrate was evaporated to dryness. The residue was washed with 25ml of ice cold water and extracted into ethyl acetate. The layers wereseparated and the organic layer was evaporated to dryness. NMR analysisconfirmed the structure of the product.

EXAMPLE 102 Preparation of1-Methyl-3-{N'-[(3'-Cyclohexyloxycarbonyl)propyl]}carbamoylpyridiniumiodide

The product of Example 102 (1.74 g, 6 mmol) was dissolved in a minimumamount of acetone and the resulting white precipitate was filtered.Methyl iodide (1.5 ml, 24 mmol) was added in one portion to thesolution, with stirring, at 0° C. The mixture was allowed to gentlyreflux overnight. Filtration of a white precipitate and evaporation ofthe yellow filtrate produced a reddish oil, which was dissolved inacetone, filtered and evaporated to dryness. Anal. calc. for C₂₂ H₂₃ O₃N₂ I: C, 47.26; H, 5.79; N, 6.48; I, 29.38. Found: C, 47.03, H, 5.85; N,6.44; I, 29.26.

EXAMPLE 103 Preparation of1-Methyl-3-{N-[(3'-cyclohexylcarbonyl)propyl]}carbamoyl-1,4-dihydropyridin

The product of Example 102 (0.11 g, 0.26 mmol) was dissolved in 25 ml ofice cold deaerated water. NaHCO₃ (0.09 g, 4-fold excess) was added,followed by Na₂ S₂ O₄ (0.14 g, 3-fold excess). Ethyl acetate (25 ml) wasadded and the mixture was stirred under nitrogen for 30 minutes. Theorganic layer was extracted and dried to give an orange oil that reducedmethanolic silver nitrate immediately. NMR analysis confirmed that theproduct has the structure: ##STR1571##

EXAMPLE 104 Preparation of3-{N-[(3'-Benzyloxycarbonyl)propyl]}carbamoylquinoline

3-Quinolinecarboxylic acid (1.55 g, 9 mmol) was dissolved in 25 ml ofdry pyridine. Dicyclohexylcarbodiimide (1.97 g, 9.6 mmol) was added anddissolved, with stirring. 4-Aminobutanoic acid benzyl esterhydrochloride (2.06 g, 9 mmol) was added and the mixture was stirred for48 hours at room temperature. The precipitated urea was removed byfiltration, the filtrate was evaporated to dryness and the residue waswashed with 10 ml of ice cold water and extracted into ethyl acetate.That solution was dried over sodium sulfate. The solvent was evaporated,the remaining residue was dissolved in acetone, filtered and evaporatedto dryness to give 2.2 g (70%) of the desired product. NMR analysisconfirmed the structure of the product.

EXAMPLE 105 Preparation of1-Methyl-3-{N-[(3'-benzyloxycarbonyl)propyl]}carbamoylquinolinium iodide

The product of Example 104 (1 g) was suspended in 25 ml of acetonitrile,the mixture was cooled on ice and 0.6 ml of CH₃ I was added in oneportion. Using an ice-water cooled condenser, the mixture was brought toa gentle reflux and refluxing was continued overnight on an oil bath.Thin layer chromatography confirmed that the resulting dark orangesolution was the desired product. Addition of CH₃ CN and evaporation ona rotovap produced a dark orange foam. Crystallization andrecrystallization with acetone/ethyl ether gave the desired product asan orange powder, m.p. 104°-105° C. Anal. calc. for C₂₂ H₂₃ N₂ O₃I.1/2H₂ O: C, 52.91; H, 4.81; N, 5.61. Found: C, 52.92; H, 4.84; N,5.60. The product has the structure: ##STR1572##

EXAMPLE 106 Preparation of1-Methyl-3-{N-[(3'-benzyloxycarbonyl)propyl]}carbamoyl-1,4-dihydroquinoline

The quaternary salt produced in Example 105 (200 mg, 0.41 mmol) wassuspended in 10 ml deaerated water. Sodium bicarbonate (0.42 g) wasadded to the solution, with stirring, followed by 0.58 g of Na₂ S₂ O₄. Ayellow color appeared immediately and the quaternary derivativedissolved. Ethyl acetate (20 ml) was added and the solution was stirredunder nitrogen for 4 hours. The layers were separated and the yelloworganic layer was dried over sodium sulfate and evaporated to dryness.The resulting yellow oil reduced methanolic silver nitrate immediately.The structure of the product was confirmed by NMR analysis to be:##STR1573##

EXAMPLE 107 Preparation of3-{N-[(3'-Cyclohexylcarbonyl)propyl]}carbamoylquinoline

3-Quinolinecarboxylic acid (1.55 g, 9 mmol) was dissolved in a minimumamount of dry pyridine. Dicyclohexylcarbodiimide (2.1 g, 10 mmol) wasadded and the solution turned yellow. 4-Aminobutanoic acid cyclohexylester hydrochloride (2 g, 9 mmol) was added and the mixture was stirredfor 2 days. The precipitated urea was removed by filtration, thefiltrate was evaporated to dryness and the residue was washed with 10 mlof ice cold water. Extraction into ethyl acetate, subsequent drying withNa₂ SO₄ and evaporation produced a yellow solid, which was dissolved inacetone, filtered and evaporated to dryness. NMR was in good agreementwith the expected spectrum.

EXAMPLE 108 Preparation of1-Methyl-3-{N-[(3'-cyclohexylcarbonyl)propyl]}carbamoylquinoliniumiodide

The product of Example 107 (1.95 g, 5.7 mmol) was dissolved in acetoneand 2 ml of methyl iodide was added in one portion, with cooling on ice.The mixture was brought to reflux slowly and allowed to refluxovernight. The dark orange reaction mixture was subsequentlycrystallized from acetone and ether to give a dark orange powder. Thestructure of the product was confirmed by NMR and UV analyses.

EXAMPLE 109 Preparation of1-Methyl-3-{N-[(3'-cyclohexylcarbonyl)propyl]}carbamoyl-1,4-dihydropyridine

The product of Example 108 (300 mg, 0.88 mmol) was suspended in 10 ml ofdeaerated water. NaHCO₃ (1.22 g) was added, followed by Na₂ S₂ O₄ (0.09g). The mixture turned yellow immediately. Ethyl acetate (20 ml) wasadded and the solution was stirred for 4 hours. The organic layer wasdried and evaporated to dryness, leaving a yellow oil which reducedmethanolic silver nitrate immediately. The product has the formula:##STR1574##

EXAMPLE 110 Preparation of L-Tryptophan ethyl ester hydrochloride

A mixture of L-tryptophan (14.3 g, 0.07 mol) in 200 ml of ethanolcontaining ˜7 g of anhydrous HCl was refluxed for 5 hours. The mixturewas cooled and the solid which separated was recrystallized fromethanol/ether. Yield 17.4 g (92.5%), m.p. 226°-228° C. The product hasthe formula: ##STR1575## The product may also be named ethylL-2-amino-3-indolepropionate.

EXAMPLE 111 Preparation ofN-[1-Ethoxycarbonyl-2-(3'-indolyl)ethyl]nicotinamide

To a solution of L-tryptophan ethyl ester hydrochloride (5.4 g, 0.02mol) and nicotinic acid (2.5 g, 0.02 mol) in 30 ml of dry pyridine wasadded dicyclohexylcarbodiimide (4.5 g, 0.022 mol). The mixture wasstirred for 24 hours at room temperature, then the urea formed wasremoved by filtration. Pyridine was evaporated under vacuum and theresidue was dissolved in 200 ml of methylene chloride. The solution waswashed with 10% NaHCO₃ and water and methylene chloride was removedunder vacuum. Yield 5.1 g (76%). NMR analysis confirmed the identity ofthe product. Anal. calc. for C₁₉ H₁₉ N₃ O₃.1/4H₂ O: C, 66.75; H, 5.75;N, 12.29. Found: C, 66.59; H, 5.92; N, 12.25.

EXAMPLE 112 Preparation of1-Methyl-3-{N-[1'-ethoxycarbonyl-2'-(3"-indolyl)ethyl]}carbamoylpyridiniumiodide

The product of Example 111 (5 g, 0.015 mmol) was dissolved in 20 ml ofmethanol and methyl iodide (5 ml, 0.08 mol) was added. The mixture wasrefluxed for 5 hours, then methanol and excess methyl iodide wereremoved under vacuum. Yield 6.9 g (96%). Anal. calc. for C₂₀ H₂₂ N₃ O₃I.3/2H₂ O: C, 47.44; H, 4.98; N, 8.30; I, 25.06. Found: C, 47.44; H,4.91; N, 8.29; I, 25.10.

EXAMPLE 113 Preparation of1-Methyl-3-{N-[1'-ethoxycarbonyl-2'-(3"-indolyl)ethyl]}carbamoyl-1,4-dihydropyridine

To a solution of 0.96 g (2 mmol) of the product of Example 112 in 5 mlof methanol, 50 ml of deaerated water and 50 ml of ethyl acette wasadded 1 g (12 mmol of NaHCO₃. To this ice-cold mixture kept undernitrogen was added 1.65 g (8 mmol) of sodium dithionite. The mixture wasstirred for 3 hours, then the ethyl acetate layer was separated and theaqueous layer was extracted with ethyl acetate. The combined ethylacetate extracts were washed with water and dried over sodium sulfate.Ethyl acetate was removed under vacuum. Yield 0.52 g (73.6%). Anal.calc. for C₂₀ H₂₃ N₃ O₃ : C, 67.97; H, 6.56; N, 11.89. Found: C, 67.67;H, 6.63; N, 11.79. The product has the structural formula: ##STR1576##

EXAMPLE 114 Prepared of1-Methyl-3-{N-[β-(3,4-dihydroxyphenyl)ethyl]carbamoyl}pyridinium iodide

To a solution of 2 g (7.7 mmol) of nicotinoyldopamine in 40 ml of drymethanol was added 2.5 g (17.6 mmol) of methyl iodide. The reactionmixture was refluxed with stirring, for 6 hours. Methyl iodide (1.5 g,1.05 mmol) was added and refluxing was continued overnight. Methanol wasremoved and ethyl acetate was added, affording yellowish crystals of thedesired product. Yield 2.4 g (77%), m.p. 173°-174° C.

EXAMPLE 115 Preparation of1-methyl-3-{N-[[β-[3,4-bis(isobutyryloxy)phenyl]ethyl]]carbamoyl}pyridiniumtrifluoroacetate

To an ice-cold solution of the product of Example 114 (3 g, 7.5 mmol) in30 ml of trifluoroacetic acid, isobutyryl chloride (2.4 g, 22.5 mmol)was added slowly, with stirring. Stirring was continued overnight atroom temperature. Trifluroracetic acid was evaporated under vacuum andthe residue was crystallized from ethyl ether:hexane (3:1). Yield 1.2 g(30.4%), m.p. 87°-91° C.

Substantial repetition of the procedure of the preceding paragraph,substituting trimethylacetyl chloride for the isobutyryl chloride usedabove, affords after appropriate purification,1-methyl-3-{N-[β-(3,4-dipivalyloxyphenyl)ethyl]carbamoyl}pyridiniumtrifluoroacetate in 72% yield (4.0 g), m.p. 158°-160° C.

EXAMPLE 116 Preparation of1-Methyl-3-{N-[[β-[3,4-bis(isobutyryloxy)phenyl]ethyl]]carbamoyl}-1,4-dihydropyridine

A solution of 0.55 g (1 mmol) of1-methyl-3-{N-[[β-[3,4-bis(isobutyryloxy)phenyl]ethyl]]carbamoyl}pyridiniumtrifluoroacetate in 50 ml of deaerated water containing 10 ml ofmethanol was extracted three times with 30 ml portions of ether. To theresultant aqueous solution was added NaHCO₃ (0.25 g, 3 mmol) and 50 mlof ethyl ether and the mixture was kept under nitrogen. To this ice-coldmixture was added sodium dithionite (0.52 g, 3 mmol) and the mixture wasstirred vigorously for 30 minutes. The ether layer was separated and theaqueous layer was extracted twice with ether. The combined etherextracts were washed with water and dried over sodium sulfate. Ether wasremoved under vacuum, leaving an oily product. NMR analysis confirmedthat the product has the structural formula: ##STR1577##

EXAMPLE 117 Preparation of5-[(3-Pyridyl)carbonyloxy]-3-{β-ethoxycarbonyl-β-[N-(3-pyridyl)carbonylamino]ethyl}indole

The ethyl ester hydrochloride of 5-hydroxytryptophan, i.e. ethylL-2-amino-3-(5-hydroxyindolyl)propionate hydrochloride, was prepared byreacting 5-hydroxy-L-tryptophan with ethanol in the presence of HCl. Toa solution of the ethyl ester hydrochloride (285 mg, 1 mmol) andnicotinic acid (246 mg, 2 mmol) in 3 ml of dry pyridine was addeddicyclohexylcarbodiimide (430 mg, 2.1 mmol). The reaction mixture wasstirred at room temperature for 24 hours and the urea formed was removedby filtration. Pyridine was removed in vacuo and the residue wasdissolved in 1 ml of methanol and 20 ml of ethyl acetate. The ethylacetate solution was washed with 10% NaHCO₃ solution and then withwater. Ethyl acetate was removed in vacuo and the residue waschromatographed on a silica gel column using 5% methanol in chloroformas the eluent. Chloroform was removed in vacuo to yield 270 mg (58.9%)of the desired product of the formula: ##STR1578##

EXAMPLE 118 Preparation of5-[(1-Methyl-3-pyridinium)carbonyloxy]-3-{β-ethoxycarbonyl-β-[N-(1-methyl-3-pyridinium)carbonylamino]ethyl}indolediiodide

The product of Example 117 (150 mg, 0.33 mmol) was dissolved in 20 ml ofmethanol and excess methyl iodide was added. The mixture was refluxedfor 4 hours and the methanol and excess methyl iodide were removed invacuo to yield 230 mg (93.9%) of the desired product. Anal. calc. forC₂₇ H₂₈ N₄ O₅ I₂ : C, 43.68; H, 3.80; N, 7.55; I, 34.19. Found: C,43.47; H, 3.86; N, 7.52; I, 34.08. NMR analysis confirmed that theproduct has the structure: ##STR1579##

EXAMPLE 119 Preparation of5-[(1-Methyl-1,4-dihydropyridin-3-yl)carbonyloxy]-3-{β-ethoxycarbonyl-β[N-(1-methyl-1,4-dihydropyridin-3-yl]carbonylamino]ethyl}indole

To a solution of the product of Example 118 (200 mg, 0.27 mmol) in 2 mlof methanol, 20 ml of deaerated water and 20 ml of ethyl acetate, 500 mgof sodium bicarbonate was added. The mixture was stirred in an ice bathunder nitrogen and 0.7 g of sodium dithionite was added. The mixture wasstirred for 5 hours. The ethyl acetate layer was decanted and the waterlayer was extracted with ethyl acetate. The combined ethyl acetatesolution was washed with water, dried over amhydrous sodium sulfate andthe solvent removed in vacuo to yield 110 mg (83.0%) of the desiredproduct. NMR analysis confirmed that the product has the structuralformula: ##STR1580##

EXAMPLE 120 Preparation of N-[β-Phenethyl) 2-bromoacetamide

To a stirred solution of 2.263 g (0.0187 mol) of phenethylamine in 10 mlof 8% sodium hydroxide solution, cooled to -10° C., were introduceddropwise 3.14 g (0.02 mol) of bromoacetyl chloride. The reaction mixturewas stirred at below -10° C. for one hour. The precipitate produced wasfiltered, washed thoroughly with cold water, dried and recrystallizedfrom chloroform, m.p. 60°-61° C., yield 3.2 g (71%); IR (KBr) 3280 (NH),1675 (CO) cm⁻¹. PMR further confirmed that the product has thestructural formula: ##STR1581##

EXAMPLE 121 Preparation of N-(β-Phenethyl) 3-bromopropionamide

The title compound was prepared similarly to the product of Example 120,but using 3-bromopropionyl chloride instead of bromoacetyl chloride.Yield 85%, rrecrystallized from aqueous ethanol, m.p. 69°-70° C.; IR(KBr) 3315 (NH), 1640 (CO) cm⁻¹. PMR further confirmed that the producthas the structural formula: ##STR1582##

EXAMPLE 122 Preparation of N-(β-Phenethyl) 4-bromobutyramide

The title compound was prepared similarly to the product of Example 120,but using 4-bromobutyryl chloride. Yield 80%, recrystallized fromaqueous ethanol, m.p. 62°-63° C.; IR (KBr) 3100 (NH), 1635 (CO) cm⁻¹.PMR further confirmed that the product has the structural formula:##STR1583##

EXAMPLE 123 Preparation of3-Carbamoyl-1-[N-(β-phenylethyl)carbamoylmethyl]pyridinium bromide

To a solution of 2.419 g (0.01 mol) of N-(β-phenethyl) 2-bromoacetamidein 20 ml dry acetonitrile were added 1.2 g (0.01 mol) of nicotinamide.The mixture was refluxed until disappearance on thin layerchromatography of the reactants (3 to 4 days). Plates of Silica Gel Gand a chloroform:methanol (9:1) sys-tem were used. The acetonitrile wasevaporated in vacuo and the residue was recrystallized frommethanol/chloroform to yield the title compound (2.8 g, 77%), m.p.178°-180° C. UV max (methanol) 265 nm; IR (KBr) 3380 (NH), 3250 (NH),1690 (CO), 1655 (CO) cm⁻¹. Anal. calc. for C₁₆ H₁₈ BrN₃ O₂.H₂ O: C,50.27; H, 5.23; N, 10.98. Found: C, 50.25; H, 4.77; N, 10.62. PMRanalysis further confirmed that the product has the structural formula:##STR1584##

EXAMPLE 124 Preparation of3-Carbamoyl-1-{2'-[N-(β-phenylethyl)carbamoyl]ethyl}pyridinium bromide

The title compound was prepared according to the procedure of Example123, using N-(β-phenethyl) 3-bromopropionamide and nicotinamide. Yield66%, recrystallized from ethanol/benzene, m.p. 120°-122° C. UV max(methanol) 266 nm; IR (KBr) 3280 (NH), 1695 (CO), 1640 (CO) cm⁻¹. Anal.calc. for C₁₇ H₂₀ BrN₃ O₂ : C, 53.98; H, 5.33; N, 11.11. Found: C,53.87; H, 5.35; N, 11.10. PMR further confirmed that the product has thestructure: ##STR1585##

EXAMPLE 125 Preparation of3-Carbamoyl-1-{3'-[N-(β-phenylethylcarbamoyl]propyl}pyridinium bromide

The title compound was prepared according to the procedure of Example123, using N-(β-phenethyl) 4-bromobutyramide and nicotinamide. Yield83%, recrystallized from ethanol/acetone, m.p. 112°-114° C. UV max(methanol) 265 nm; IR (KBr) 3350 (NH), 3320 (NH), 1692 (CO), 1642 (CO)cm⁻¹. Anal. calc. for C₁₈ H₂₂ BrN₃ O₂ : C, 55.11; H, 5.65; N, 10.71.Found: C, 54.93; H, 5.67; N, 10.70. PMR further confirmed the structureof the product to be: ##STR1586##

EXAMPLE 126 Preparation of3-Carbamoyl-1-[N-(β-phenylethyl)carbamoylmethyl]-1,4-dihydropyridine

To a solution of 3.64 g (0.01 mol) of the product of Example 123 in 150ml of deareated 15% aqueous methanol were added 5.04 g (0.06 mol) ofsodium bicarbonate. The mixture was stirred in an ice bath, and 6.96 g(0.04 mol) of slodium dithionite were added over a period of 5 minutes.The reaction mixture was stirred for one hour under nitrogen and a paleyellow crystalline precipitate was formed. The precipitate was filtered,washed with water, and recrystallized from aqueous methanol, m.p.126°-128° C., yield 2.4 g (84%). UV max (methanol) 348 nm; IR (KBr) 3280(NH), 1680 (CO), 1645 (CO) cm⁻¹. Anal. calc. for C₁₆ H₁₉ N₃ O₂.3/4H₂ O:C, 64.30; H, 6.91; N, 14.06. Found: C, 64.32; H, 6.91; N, 14.06. Thestructure of the product was further confirmed by PMR to be: ##STR1587##

EXAMPLE 127 Preparation of3-Carbamoyl-1-{2'-[N-(β-phenylethyl)carbamoyl]ethyl}-1,4-dihydropyridine

The product of Example 124 (3.78 g, 0.01 mol) was reduced according tothe procedure described in Example 126 with sodium dithionite (6.96 g,0.04 mol). After completion of the reaction, the product was extractedwith ethyl acetate, washed with water, dried over anhydrous sodiumsulfate, and the solvent was evaporated in vacuo. A yield of 2.4 g (80%)of the title compound was obtained as a yellowish amorphous powder, m.p.121°-123° C. UV max (methanol) 350 nm; IR (KBr) 3430 (NH), 3260 (NH),1670 (CO), 1630 (CO) cm⁻¹. Anal. calc. for C₁₇ H₂₁ N₃ O₂.3/4H₂ O: C,65.26; H, 7.24; N, 13.43. Found: C, 65.19; H, 6.87; N, 13.61. Thestructure of the product was further confirmed by PMR to be: ##STR1588##

EXAMPLE 128 Preparation of3-Carbamoyl-1-{3'-[N-(β-phenylethyl)carbamoyl]propyl}-1,4-dihydropyridine

The product of Example 125 (3.92 g, 0.01 mol) was reduced with sodiumdithionite (6.96 g, 0.04 mol) according to the procedure of Example 126.A yield of 2.2 g (65%) of the title compound was obtained as anorange-yellow amorphous powder, m.p. 55°-60° C. UV max (methanol) 358nm; IR (CHCl₃) 3325 (NH), 1682 (CO), 1645 (CO) cm⁻¹. Anal. calc. for C₁₈H₂₃ N₃ O₂.3/4H₂ O: C, 66.07; H, 7.49; N, 12.85. Found: C, 66.05; H,7.56; N, 12.84. The structure of the product was further confirmed byPMR to be: ##STR1589##

EXAMPLE 129 Preparation of 17β-[(Bromoacetyl)oxy]androst-4-en-3-one(Testerosterone bromoacetate)

To a solution of 2.884 g (0.01 mol) of testosterone in 30 ml of drybenzene was added 1.008 g (0.012 mol) of sodium bicarbonate; then, whilestirring, there were introduced dropwise 1.888 g (0.012 mol) ofbromoacetyl chloride over a 5 minute period. The reaction mixture wasthen stirred under reflux for 6 hours until no testosterone could betraced by TLC. (Plates of Silica Gel G and a CHCH₃ /CH₃ OH system wereused.) The inorganic residue was filtered while hot, the filtrate wasevaporated in vacuo and the residue was recrystallized from methanol,m.p. 144°-145° C., yield 3.2 g (78%). IR (KBr) 1735 (C═O), 1660 (C═O)cm⁻¹. PMR as expected. The product has the formula: ##STR1590##

EXAMPLE 130 Preparation of17β-[(3'-Bromopropionyl)oxy]androst-4-en-3-one (Testosteroneβ-bromopropionate)

The title compound was prepared according to the method of Example 129,but using 3-bromopropionylchloride. Yield 80%, recrystallized frommethanol, m.p. 153°-154° C. IR (KBr) 1740 (C═O), 1667 (C═O) cm⁻¹. PMR asexpected. The product has the structural formula: ##STR1591##

EXAMPLE 131 Preparation of17β-{(±)[2'-Bromopropionyl]oxy}androst-4-en-3-one (Testosteroneα-bromopropionate)

The title compound was made according to Example 129, but using (±)2-bromopropionyl chloride. Yield 80%, recrystallized from methanol, m.p.187°-188° C. IR (KBr) 1732 (C═O), 1658 (C═O) cm⁻¹. PMR as expected. Theproduct has the formula: ##STR1592##

Similarly prepared using 4-bromobutyryl chloride was17β-[(4'-bromobutyryl)oxy]androst-4-en-3-one, having the formula:##STR1593##

EXAMPLE 132 Preparation of17β-{[(3"-Carbamoyl-1"-pyridinium)acetyl]oxy}androst-4-en-3-one bromide

To a solution of 4.09 g (0.01 mol) of testosterone bromoacetate in 30 mlof dry acetonitrile was added 1.22 g (0.01 mol) of nicotinamide. Themixture was refluxed until complete disappearance of the reactants (2 to3 days) as detected by TLC (Plates and solvents as in Example 129). Oncooling, a white crystalline precipitate was produced, which wasfiltered, washed with aetonitrile and recrystallized from acetonitrile.Yield 3.62 g (68%), m.p. 237°-238° C. UV max (methanol) 236.5 nm; IR(KBr) 3130 (NH), 1745 (C═O), 1680 (C═O) cm⁻¹ ; PMR as expected. Anal.calc. for C₂₇ H₃₅ BrN₂ O₄.1/2H₂ O: C, 60.00; H, 6.66; N, 5.18. Found: C,59.87; H, 6.70; N, 5.17. The product has the formula: ##STR1594##

EXAMPLE 133 Preparation of17β-{[3'-(3"-Carbamoyl-1"-pyridinium)propionyl]oxy}androst-4-en-3-onebromide

The title compound was prepared as the product of Example 132 usingequimolar amounts of testosterone β-bromopropionate and nicotinamide.Yield 60%, recrystallized from methanol/acetonitrile, m.p. 215°-216° C.UV max (methanol) 238 nm; IR (KBr) 3150 (NH), 1720 (C═O), 1670 (C═O)cm⁻¹ ; PMR as expected. Anal. calc. for C₂₈ H₃₇ BrN₂ O₄ : C, 61.65; H,6.79; N, 5.14. Found: C, 61.39; N, 6.89; N, 5.07. The product has theformula: ##STR1595##

EXAMPLE 134 Preparation of17β-{[(±)2'-(3"-Carbamoyl-1"-pyridinium)propionyl]oxy}androst-4-en-3-onebromide

The title compound was prepared as in Example 132 using equimolaramounts of testosterone α-bromopropionate and nicotinamide. Yield 60%,recrystallized from acetonitrile, m.p. 236°-237° C. UV max (methanol)237 nm. IR (KBr) 3080 (NH), 1740 (C═O), 1670 (C═O) cm⁻¹. PMR asexpected. Anal. calc. for C₂₈ H₃₇ BrN₂ O₄ : C, 61.65; H, 6.79; N, 5.14.Found: C, 61.52; H, 6.81; N, 5.12. The product has the formula:##STR1596##

Similarly prepared using 17β-[(4'-bromobutyryl)oxy]androst-4-en-3-oneand nicotinamide was17β-{[4'-(3"-carbamoyl-1"-pyridinium)butyryl]oxy}androst-4-en-3-onebromide, having the formula: ##STR1597##

EXAMPLE 135 Preparation of17β-{[(3"-Carbamoyl-1",4"-dihydropyridinyl)acetyl]oxy}androst-4-en-3-one

To an ice-cold solution of 1.593 g (0.003 mol) of the product of Example132 in 150 ml of deaerated 25% aqueous methanol were added 1.512 g(0.018 mol) of sodium carbonate and 2.088 g (0.012 mol) of sodiumdithionite. The mixture was stirred for 30 minutes at 0° C. undernitrogen. The dihydro product formed was extracted with dichloromethane,washed with water and dried over anhydrous slodium sulfate. The filtratewas flushed with dry nitrogen, and the solvent was evaporated in vacuoat ambient temperature. The residue was dried over P₂ O₅ under vacuum toyield 0.98 g (72%) of the title compound, m.p. 160°-165° C. Alcoholicsolution shows immediate reduction to alcoholic solution of silvernitrate. UV max (methanol) 342 nm; IR (KBr) 3160 (NH), 1730 (C═O), 1655(C═O) cm⁻¹. PMR as expected. Anal. calc. for C₂₇ H₃₆ N₂ O₄.3H₂ O: C,64.03; H, 8.30; N, 5.53. Found: C, 63.54; H, 7.94; N, 5.59. The producthas the formula: ##STR1598##

EXAMPLE 136 Preparation of17β-{[3'-(3"-Carbamoyl-1",4"-dihydropyridinyl)propionyl]oxy}androst-4-en-3-one

The title compound was prepared according to the method of Example 135,utilizing the product of Example 133 as starting material, in a 56%yield as a yellowish amorphous powder, m.p. 75°-77° C. The product'salcoholic solution shows immediate reduction to alcoholic solution ofsilver nitrate. UV max (methanol) 346 nm; IR (KBr) 3200 (NH), 1725(C═O), 1665 (C═O) cm⁻¹ ; PMR as expected. Anal. calc. for C₂₈ H₃₈ N₂O₄.3H₂ O: C, 64.62; H, 8.46; N, 5.38. Found: C, 64.59; H, 7.78; N, 5.19.The product has the formula: ##STR1599##

EXAMPLE 137 Preparation of17β-{[(±)2'-(3"-Carbamoyl-1",4"-dihydropyridinyl)propionyl]oxy}androst-4-en-3-one

The title compound was prepared by the method of Example 135, using theproduct of Example 134, first paragraph, as starting material, in a 78%yield as a yellowish amorphous powder, m.p. 145°-150° C. Its alcoholicsolution shows immediate reduction to alcoholic solution of silvernitrate. UV max (methanol) 344 nm; IR (KBr) 3160 (NH), 1725 (C═O), 1655(C═O) cm⁻¹ ; PMR as expected. Anal. calc. for C₂₈ H₃₈ N₂ O₄.2H₂ O: C,66.93; H, 8.36; N, 5.57. Found: C, 66.79; H, 7.69; N, 5.43. The producthas the formula: ##STR1600##

Similarly prepared from17β-{[4'-(3"-carbamoyl-1"-pyridinium)butyryl]oxy}androst-4-en-3-onebromide was17β-{[4'-(3"-carbamoyl-1",4"-dihydropyridinyl)butyryl]oxy}androst-4-en-3-one,having the structural formula: ##STR1601##

EXAMPLE 138 Preparation of5,5-Diphenyl-3-hydroxymethyl-2,4-imidazolidinedione

Phenytoin (5 g, 0.02 mol) was suspended in 180 ml of water; 20 ml offormaldehyde (37% solution) and 0.25 g K₂ CO₃ were added and the mixturewas stirred at 25°-30° C. for 24 hours. The white solid which formed wasremoved by filtration and washed repeatedly with a 3% solution offormaldehyde, then air dried for 3 to 4 hours and over P₂ O₅ in a vacuumdessicator. Yield 91-93%, m.p. 185°-189° C. Anal. calc. for C₁₆ H₁₄ N₂O₃ : C, 68.07; H, 5.00; N, 9.93. Found: C, 67.97; H, 5.05; N, 9.93. Theproduct has the formula: ##STR1602##

EXAMPLE 139 Preparation of5,5-Diphenyl-3-[(3'-pyridyl)carbonyloxymethyl]-2,4-imidazolidinedione

The product of Example 138 (3.00 g, 0.011 mol) was dissolved in 150 mlof dry pyridine, then nicotinic anhydride (4.25 g, 0.019 mol) was added.The resultant solution was stirred at room temperature (25°-30° C.),under dry conditions, for 40 hours. The solution was poured into 2.5 lof water and the resultant white solid was removed by filtration, washedwell with water and dried over P₂ O₅ in a vacuum dessicator. 95% yield,m.p. 178°-182° C. Anal. calc. for C₂₂ H₁₇ N₃ O₄ : C, 68.21; H, 4.42; N,10.85. Found: C, 68.12; H, 4.43; N, 10.83. The product has the formula:##STR1603##

EXAMPLE 140 Preparation of5,5-Diphenyl-3-[(1'-methyl-3'-pyridinium)carbonyloxymethyl]-2,4-imidazolidinedioneiodide

The product of Example 139 (0.5 g, 0.0013 mol) was dissolved in 50 ml ofacetonitrile, then 0.3 ml of methyl iodide was added and the reactionmixture was maintained at room temperature for 6 days. The solvent wasremoved by vacuum distillation and ethyl ether was added to the residue.The ether solution was refrigerated for 2 hours, then the yellow,hygroscopic crystals which formed were dried over P₂ O₅ in a vacuumdessicator, giving the desired product in 85% yield. UV and H¹ NMRspectra confirmed that the product has the structure: ##STR1604##

Repeating the above procedure in nitromethane at a 50°-70° C. bathtemperature using excess methyl iodide, added gradually, for 5 to 6hours, afforded the same product in nearly quantitative yield.

EXAMPLE 141 Preparation of5,5-Diphenyl-3-[(1'-methyl-1',4'-dihydropyridin-3'-yl)carbonyloxymethyl]-2,4-imidazolidinedione:

The quaternary salt obtained in Example 140 (0.4 g, 0.0008 mol) wasdissolved in 40 ml of water, 3 ml of methanol and 15 ml of ethylacetate. The reaction mixture was cooled to 0° to 5° C. and deaerated,then sodium bicarbonate (0.39 g, 0.0046 mol) and sodium dithionite (0.54g, 0.0032 mol) were added. The mixture was stirred under nitrogen at0°-5° C. for 35 minutes. The organic layer was removed and the aqueouslayer was extracted twice with 15 ml portions of ethyl acetate and theorganic solutions were extracted with 10 ml of cold deaerated water.After drying over Na₂ SO₄, the solvent was removed by vacuumdistillation and the oily yellow solid was crystallized by addition ofether. Yield 70%. UV and H¹ -NMR analyses confirmed that the product hasthe formula ##STR1605##

EXAMPLE 142 Preparation of3-Bromoacetyloxymethyl-5,5-diphenyl-2,4-imidazolidinedione

5,5-Diphenyl-3-hydroxymethyl-2,4-imidazolidinedione (2 g, 0.0071 mol)was dissolved in bromoacetylchloride (15 g, 8 ml, 0.096 mol) by heatingin an oil bath (70°-80° C. bath temperature) for about 15 minutes, untilthe formation of HCl ceased. The mixture was cooled and 30 ml of ethylether were added. White crystals formed. The mixture was cooled to 0°C., then the crystals were removed by filtration and dried over P₂ O₅.Yield: 2.15 g (75%), m.p. 179°-183° C. Anal. calc. for C₁₈ H₁₅ N₂ O₄ Br:C, 53.61; H, 3.75; N, 6.95; Br, 19.82. Found: C, 53.60; H, 3.79; N,6.92; Br, 19.90. The product has the formula: ##STR1606##

EXAMPLE 143 Preparation of3-(3'-Bromopropionyl)oxymethyl-5,5-diphenyl-2,4-imidazolidinedione

5,5-Diphenyl-3-hydroxymethyl-2,4-imidazolidinedione (5 g, 0.018 mol) wasreacted according to the procedure of Example 142 with 3-bromopropionylchloride (6.8 g, 0.04 mol, 4 ml), using a bath temperature of 100° C. Awhite crystalline product was obtained in 65% yield (4.9 g), m.p.133°-134° C. Anal. calc. for C₁₉ H₁₇ N₂ O₄ Br: C, 54.69; H, 4.11; N,6.72; Br, 19.15. Found: C, 54.79; H, 4.12; N, 6.69; Br, 19.25. Theproduct has the formula: ##STR1607##

EXAMPLE 144 Preparation of3-(2'-Bromopropionyl)oxymethyl-5,5-diphenyl-2,4-imidazolidinedione:

5,5-Diphenyl-3-hydroxymethyl-2,4-imidazolidinedione (2 g, 0.0071 mol)was dissolved in 2-bromopropionyl chloride (8.5 g, 5 ml, 0.05 mol) byheating for 30 minutes on a 100°-110° C. oil bath. The reaction mixturewas cooled, 20 ml of ethyl ether were added, and the resultant solutionwas extracted with aqueous potassium carbonate, dried and thencrystallized. The product was obtained as a solid white substance (1 g,34%), m.p. 112°-115° C. Anal. calc. for C₁₉ H₁₇ N₂ O₄ Br: C, 54.69; H,4.11; N, 6.72; Br, 19.15. Found: C, 54.77; H, 4.15; N, 6.69; Br, 19.25.The product has the formula: ##STR1608##

EXAMPLE 145 Preparation of3-(3'-Carbamoyl-1'-pyridinium)acetyloxymethyl-5,5-diphenyl-2,4-imidazolidinedionebromide:

The product of Example 142 (2.02 g, 0.005 mol) dissolved in 15 ml ofnitromethane was mixed with nicotinamide (0.61 g, 0.005 mol). Thesolution was stirred on a 90°-100° c. temperature oil bath for 2 hours.The mixture was cooled to 60°-70° C. and the white crystals which hadformed were removed by filtration and washed with nitromethane. Yield61% (1.65 g), m.p. 193°-197° C. (dec). Anal. calc. for C₂₄ H₂₁ N₄ O₅ Br:C, 54.87; H, 4.03; N, 10.67; Br, 15.21. Found: C, 54.70; H, 4.05; N,10.64; Br, 15.25. The product has the formula: ##STR1609##

EXAMPLE 146 Preparation of3-[3'-(3"-Carbamoyl-1"-pyridinium)propionyloxymethyl]-5,5-diphenyl-2,4-imidazolidinedionebromide

The product of Example 143 (2.09 g, 0.005 mol) was dissolved in 15 mlacetonitrile, then nicotinamide (0.61 g, 0.005 mol) was added. Thesolution was refluxed for 6 days, then the solvent was removed. To thegum-like residue, 30 ml of ethyl ether was added and the mixture wasstirred for 2 hours. The white substance which formed was removed byfiltration ad washed with ether. Yield 78% (2.1 g); m.p. 98°-100° C.(dec.); UV and H¹ NMR as expected. The product has the formula:##STR1610##

EXAMPLE 147 Preparation of3-[2'-(3"-Carbamoyl-1"-pyridinium)propionyloxymethyl]-5,5-diphenyl-2,4-imidazolidinedionebromide

The product of Example 144 (0.69 g, 0.00165 mol) was dissolved in 8 mlof acetonitrile, then nicotinamide (0.2 g, 0.00165 mol) was added andthe solution was refluxed for 22 hours. The silvent was removed from theresultant brown noncrystalline substance at 50° C., then ethyl ether (15ml) was added and the mixture was stirred for 2 hours. The light brownsubstance was removed by filtration and washed with ether. Yield 56%(0.5 g), m.p. 158° C. (dec.). The product has the formula: ##STR1611##

EXAMPLE 148 Preparation of3-[(3'-Carbamoyl-1',4'-dihydropyridin-1'-yl)acetyloxymethyl]-5,5-diphenyl-2,4-imidazolidinedione

The product of Example 145 (0.52 g, 0.001 mol) was dissolved in amixture of 60 ml of water and 30 ml of ethyl acetate. The mixture wascooled at 5° C. and deaerated, then sodium bicarbonate (0.5 g, 0.006mol) and sodium dithionite (0.7 g, 0.004 mol) were added and theresultant mixture was stirred, with deaeration and cooling, for 30minutes. The layers were separated and the aqueous layer was extractedwith 30 ml of ethyl acetate. The organic solution was extracted with 20ml of cooled, deaerated water. After drying over sodium sulfate, thesolvent was removed. Yield 55% (0.25 g) of yellow crystals, melting at155°-160° C. (dec.). The product reduced alcoholic silver nitratesolution and has the formula: ##STR1612##

The products of Examples 146 and 47 can be similarly reduced to thecorresponding dihydro derivatives.

EXAMPLE 149 Preparation of3-(3'-Pyridyl)acetyloxymethyl-5,5-diphenyl-2,4-imidazolidinedione

3-Pyridylacetic acid hydrochloride (0.87 g, 0.005 mol) and5,5-diphenyl-3-hydroxymethyl-2,4-imidazolidinedione (1.41 g, 0.005 mol)were dissolved in 14 ml of dry pyridine, then dicyclohexylcarbodiimide(1.03 g, 0.005 mol) in 2 ml of pyridine was added. The reaction mixtureturned yellow. The mixture was stirred at room temperature for 24 hours,then the urea which formed was removed by filtration and the solvent wasremoved by vacuum distillation. Methylene chloride (10 ml) was added tothe residue and, after 10 minutes, a small amount of urea was removee byfiltration. The organic solution was extracted with potassium carbonate(1 g) dissolved in 25 ml of water, then dried and concentrated. Ethylether was added to the oily residue, and white crystals formed. Aftercooling, the product was removed by filtration, washed with ether anddried. Yield 65% (1.3 g), m.p. 157°-161° C. Anal. calc. for C₂₃ H₁₉ N₃O₄ : C, 68.82; H, 4.77; N, 10.49. Found: C, 68.49; H, 5.28; N, 10.39.The product has the structure: ##STR1613##

EXAMPLE 150 Preparation of3-(1'-Methyl-3'-pyridinium)acetyloxymethyl-5,5-diphenyl-2,4-imidazolidinedioneiodide

The product of Example 149 (0.4 g, 0.001 mol) was dissolved in 20 ml ofnitromethane, methyl iodide (0.9 g, 0.4 ml, 0.006 mol) was added and themixture was warmed for 2 hours at 70° C. on an oil bath. Removal ofsolvent by vacuum distillation afforded a yelllow crystalline productmelting at 110°-115° C. Yield 100% (0.54 g). The product has thestructure: ##STR1614##

That material can then be reduced using sodium dithionite as generallydescribed hereinabove, to afford the corresponding dihydro derivative ofthe formula: ##STR1615##

EXAMPLE 151 Preparation of10,11-Dihydro-N-methyl-N-(3-pyridyl)carbonyl-5H-dibenz(b,f)azepine-5-propanamine

Freshly prepared nicotinoyl chloride hydrochloride (0.55 g, 0.003 mol)was suspended in methylene chloride (12 ml) cooled to 5° C. and sodiumbicarbonate (0.053 g, 0.0063 mol) was added. After 5 minutes,desipramine hydrochloride (0.75 g, 0.0025 mol) was added and the mixturewas stirred for 3 hours at 5° C. The sodium chloride was removed byfiltration and the organic solution was extracted with aqueous sodiumbicarbonate, dried over sodium sulfate, filtered through Celite™ andconcentrated. Ethyl ether (5 ml) was added to the oily residue and whitecrystals formed. Yield 62% (0.58 g), m.p. 84°-86° C. The product has theformula: ##STR1616##

EXAMPLE 152 Preparation of10,11-Dihydro-N-methyl-N-(1-methyl-3-pyridinium)carbonyl-5H-dibenz(b,f)azepine-5-propanamineiodide

The product of Example 151 (0.3 g, 0.0008 mol) was dissolved in 10 ml ofnitromethane, methyl iodide (0.7 g, 0.3 ml, 0.005 mol) was added and themixture was maintained at 24 hours at room temperature. The solvent wasremoved by vacuum distillation, ethyl ether was added to the residue andhygroscopic crystals of the desired product were obtained. Yield 90%(0.37 g), m.p. 110° C. (dec.). The product has the formula ##STR1617##

The material can then be reduced as generally described hereinabove, toafford the corresponding dihydro derivative,10,11-dihydro-N-methyl-N-(1-methyl-1,4-dihydropyridin-3-yl)carbonyl-5H-dibenz(b,f)-azepine-5-propanamine,having the formula: ##STR1618##

EXAMPLE 153 Preparation of N-Nicotinoyloxysuccinimide

Nicotinic acid (4.025 g, 0.0327 mol) and N-hydroxysuccinimide (3.763 g,0.0327 mol) were dissolved in 130 ml of dioxane.Dicyclohexylcarbodiimide (6.75 g, 0.032 mol in 20 ml of dioxane wasadded. The reaction mixture was then stirred at room temperature for 3hours. The dicyclohexylurea which precipitated was removed by filtrationand the solvent was removed by rotary evaporation. The crude product wasrecrystallized from ethyl acetate to give light yellow crystals whichare then washed with anhydrous ether. The product, obtained in 72% yield(5.2 g) and melting at 129°-131° C., has the formula: ##STR1619##

EXAMPLE 154 Preparation ofN-[(1-methyl-3-pyridinium)carbonyloxy]succinimide iodide

N-Nicotinoyloxysuccinimide (5.0 g, 0.0227 mol) was dissolved in 80 ml ofdioxane and methyl iodide (4.24 ml, 0.0683 mol) was added. The reactionmixture was refluxed at 70° C. overnight. The solution changed to a redcolor while a yellow precipitate formed. The precipitate was removed byfiltration, washed thoroughly with anhydrous ether and dried. Yield 87%(7.134 g) of the quaternized product of the formula: ##STR1620##

EXAMPLE 155 Preparation of2-Amino-1,9-dihydro-9-{[2-(1'-methyl-3'-pyridinium)carbonyloxyethoxy]methyl}-6H-purin-6-oneiodide

Acyclovir sodium salt was converted to the free acid by first dissolvingit in water (10 ml) and then adding a few drops of 0.01M HCl, until someprecipitation was observed. The precipitate was centrifuged and to thesupernatant was added a few more drops of 0.01M HCl to ensure completeprecipitation of the free acid. Complete precipitation was achieved withthe pH at 11.00. The percipitate thus obtained was washed well withsmall amounts of ice-cold water and then with anhydrous ether andallowed to dry.

The quaternized activated ester obtained in Example 154 (0.72 g, 0.002mol) was dissolved in 50 ml of dimethylformamide and acyclovir (0.450 g,0.002 mol) in 50 ml of dimethylformamide was added. The reaction mixturewas stirred at room temperature for 7 days, then one additionalequivalent of the activated ester was added and the reaction mixture wasstirred at 50° C. for 3 days. The volume of solvent was reduced byrotary evaporation and the residue was allowed to stand overnight. Thelight yellow crystals thus obtained were separated and dried. Theproduct melted at 220°-224° C. and was assigned the structure depictedbelow: ##STR1621##

That product can then be reduced with sodium dithionite as generallydescribed hereinabove, to afford the corresponding dihydro derivative,2-amino-1,9-dihydro-9-{[2-(1'-methyl-1',4'-dihydropyridin-3'-yl)carbonyloxyethoxy]methyl}-6H-purin-6-one,having the formula: ##STR1622##

In the discussion to follow, the expression "at least one reactivefunctional group selected from the group consisting of amino, hydroxyl,mercapto, carboxyl, amide and imide" and portions of that expression areused. The functional groups designated in that expression have thefollowing meanings:

The word "amino" means a primary or secondary amino function, i.e. --NH₂or --NHR. The secondary amino function is also represented herein as--NH--, particularly since the exact identity of the R portion of --NHRis immaterial, R being a part of the drug residue D itself which is leftunchanged by this invention.

The word "hydroxyl" means an --OH function.

The word "carboxyl" means a --COOH function.

The word "mercapto" means an --SH function.

The word "amide" means a carbamoyl (--CONH₂) or substituted carbamoyl(--CONHR) or a sulfamoyl (--SO₂ NH₂) or substituted sulfamoyl (--SO₂NHR) functional group. The --CONHR and --SO₂ NHR groups may also berepresented herein as --CONH-- and --SO₂ NH--, respectively, since theidentity of R is immaterial, R being a part of the drug residue D isitself which is left unchanged by this invention.

The word "imide" means a functional group having the structure##STR1623## that is, the structure which characterizes imides (i.e.compounds having a succinimide-type or phthalimide-type structure).

The many different dihydropyridine⃡pyridinium salt redox carrier moietiesillustrated for use hereinabove are merely exemplary of the many classesof carriers contemplated by this invention. While the following list ofcarrier classes is not meant to be exhaustive (and, indeed, yet othercarrier classes are illustrated both hereinabove and hereinbelow), thefollowing major classes of quaternaries and the corresponding dihydroforms are prime examples of the moieties encompassed hereby:

(1) For linkage to a drug having at least one hydroxyl or mercapto orprimary or secondary amino functional grouping, replacing a hydrogenatom from at least one of said functional groupings with one of thefollowing [QC^(+]) groupings: ##STR1624## wherein R₁ is C₁ -C₇ alkyl, C₁-C₇ haloalkyl or C₇ -C₁₀ aralkyl; R₃ is C₁ to C₃ alkylene; X is--CONR'R" wherein R' and R", which can be the same or different, areeach H of C₁ -C₇ alkyl, or X is --CH--NOR"' wherein R"' is H or C₁ -C₇alkyl; the carbonyl-containing groupings in formulas (a) and (c) and theX substituent in formula (b) can each be attached at the 2, 3 or 4position of the pyridinium ring; the carbonyl-containing groupings informulas (d) and (f) and the X substituent in formula (e) can each beattached at the 2, 3 or 4 position of the quinolinium ring; and thecarbonyl-containing groupings in formulas (g) and (j) and the Xsubstituent in formula (h) can each be attached at the 1, 3 or 4position of the isoquinolinium ring;

(2) For linkage to a drug having at least one carboxyl functionalgrouping, replacing a hydrogen atom from at least one of said carboxylgroupings with one of the following [QC⁺ ] groupings:

(a) When there are one or more --COOH groups to be derivatized:##STR1625## wherein Z' is C₁ -C₈ straight or branched alkylene,preferably C₁ -C₃ straight or branched alkylene; Q is --O-- or --NH--;R₁ is C₁ -C₇ alkyl, C₁ -C₇ haloalkyl or C₇ -C₁₀ aralkyl; R₃ is C₁ -C₃alkylene, X is --CONR'R" wherein R' and R", which can be the same ordifferent, are each H or C₁ -C₇ alkyl, or X is --CH═NOR"' wherein R"' isH or C₁ -C₇ alkyl; the X substituent in formula (ii) and thecarbonyl-containing groupings in formulas (i) and (iii) can each beattached at the 2, 3 or 4 position of the pyridinium ring; the xsubstituent in formula (v) and the carbonyl-containing groupings informulas (iv) and (vi) can each be attached at the 2, 3 or 4 position ofthe quinolinium ring; and the X substituent in formula (viii) andcarbonyl-containing groupings in formulasd (vii) and (ix) can each beattached at the 1, 3 or 4 position of the isoquinolinium ring;

(b) Alternatively, when there is only one --COOH group to bederivatived: ##STR1626## wherein  is the skeleton of a sugar molecule;n^(iv) is a positive integer equal to the total number of --OH functionsin the sugar molecule from which said skeleton is derived; n^(v) is apositive integer one less than the total number of --OH functions in thesugar molecule from which said skeleton is derived; each A in each ofstructures (xii), (xiii) and (xiv) can independently be hydroxy or D',D' being the residue of a centrally acting drug containing one reactivecarboxyl functional group, said residue being characterized by theabsence of a hydrogen atom from said carboxyl functional group in saiddrug; and each R'₄ in each of structures (x) and (xi) can independentlybe hydroxy, ##STR1627## wherein D' is defined as with structures (xii),(xiii) and (xiv); R₁ is C₁ -C₇ alkyl, C₁ -C₇ haloalkyl or C₇ -C₁₀aralkyl; and the depicted carbonyl-containing groupings can be attachedat the 2, 3 or 4 position of the pyridinium or quinolinium ring, or atthe 1, 3 or 4 position of the isoquinolinium ring; with the proviso thatat least one R'₄ in each of structures (x) and (xi) is ##STR1628##wherein R₁ and the position of the carbonyl-containing groupings aredefined as above; and with the further proviso that when more than oneof the R'₄ radicals in a given compound are the aforesaidcarbonyl-containing groupings, then all such carbonyl-containinggroupings in said compound are identical.

(3) For linkage to a drug having at least one --NH-- functional groupwhich is part of an amide or imide structure or at least one low pKaprimary or secondary amine functional group, replacing a hydrogen atomfrom at least one of said functional groupings with one of the following[QC⁺ ] groupings: ##STR1629## wherein R₁ is C₁ -C₇ alkyl, C₁ -C₇haloalkyl or C₇ -C₁₀ aralkyl; R is hydrogen, C₁ -C₇ alkyl, C₃ -C₈cycloalkyl, C₁ -C₇ haloalkyl, furyl, phenyl, or phenyl substituted byone or more halo, lower alkyl, lower alkoxy, carbamoyl, loweralkoxycarbonyl, lower alkanoyloxy, lower haloalkyl, mono(loweralkyl)carbamoyl, di(lower alkyl)carbamoyl, lower alkylthio, loweralkylsulfinyl or lower alkylsulfonyl; R₃ is C₁ to C₃ alkylene; X is--CONR'R" wherein R' and R", which can be the same or different, areeach H or C₁ -C₇ alkyl, or X is --CH═NOR"' wherein R"' is H or C₁ -C₇alkyl; the carbonyl-containing groupings in formulas (k) and (m) and theX substituent in formula (1) can each be attached at the 2, 3 or 4position of the pyridinium ring; the carbonyl-containing groupings informulas (n) and (p) and the X substituent in formula (o) can each beattached at the 2, 3 or 4 position of the quinolinium ring; and thecarbonyl-containing groupings in formulas (q) and (s) and the Xsubstituent in formula (r) can each be attached at the 1, 3 or 4position of the isoquinolinium ring. Here and throughout thisapplication, the expression "C₁ -C₇ haloalkyl" means C₁ -C₇ alkylsubstituted by one or more halogen atoms. Also here and throughout thisapplication, the alkyl radicals, including alkyl and alkylene portionsof other radicals, can be straight or branched unless otherwisespecified.

Drugs containing secondary or tertiary hydroxyl functional groups can belinked to any of the [QC⁺ ] groupings (k) through (s) above in which the##STR1630## portion is derived from an aldehyde RCH₂ O capable ofreacting with said drug to form the corresponding hemiacetal, asdiscussed in more detail in Method K' hereinabove.

The dihydro forms [DHC] corresponding to the aforementioned quaternariesare as follows:

(1') For Group (1) above: ##STR1631## wherein the dotted line informulas (a'), (b') and (c') indicates the presence of a double bond ineither the 4 or 5 position of the dihydropyridine ring; the dotted linein formulas (d'), (e') and (f') indicates the presence of a double bondin either the 2 or 3 position of the dihydroquinoline ring; R₁ is C₁ -C₇alkyl, C₁ -C₇ haloalkyl or C₇ -CH₁₀ aralkyl; R₃ is C₁ to C₃ alkylene; Xis --CONR'R", wherein R' and R", which can be the same or different, areeach H or C₁ -C₇ alkyl, or X is --CH═NOR"' wherein R"' is H or C₁ -C₇alky; the carbonyl-containing groupings in formulas (a') and (c') andthe X substituent in formula (b') can each be attached at the 2, 3 or 4position of the dihydropyridine ring; the carbonyl-containing groupingsin formulas (d') and (f') and the X substituent in formula (e') can eachbe attached at the 2, 3 or 4 position of the dihydroquinoline ring; andthe carbonyl-containing groupings in formulas (g') and (j') and the Xsubstituent in formula (h') can each be attached at the 1, 3 or 4position of the dihydroisoquinoline ring;

(2') For Group (2) (a) above: ##STR1632## wherein the dotted line informulas (i'), (ii') and (iii') indicates the presence of a double bondin either the 4 or 5 position of the dihydropyridine ring; the dottedline in formulas (iv'), (v') and (vi') indicates the presence of adouble bond in either the 2 or 3 position of the dihydroquinoline ring;Z' is C₁ -C₈ straight or branched alkylene, preferably C₁ -C₃ straightor branched alkylene; Q is --O-- or --NH--; R₁ is C₁ -C₇ alkyl, C₁ -C₇haloalkyl or C₇ -C₁₀ aralkyl; R₃ is C₁ -C₃ alkylene; X is --CONR'R"wherein R' and R", which can be the same or different, are each H or C₁-C₇ alkyl, or X is --CH═NOR"' wherein R"' is H or C₁ -C₇ alkyl; the Xsubstituent in formula (ii') and the carbonyl-containing grouping informulas (i') and (iii') can each be attached at the 2, 3 or 4 positionof the dihydropyridine ring; the X substituent in formula (v') and thecarbonyl-containing groupings in formulas (iv') and (vi') can each beattached at the 2, 3 or 4 position of the dihydroquinoline ring; and theX substituent in formula (viii') and the carbonyl-containing groupingsin formulas (vii') and (ix') can each be attached at the 1, 3 or 4position of the dihydroquinoline ring.

(3') For Group (2) (b) above: ##STR1633## wherein the dotted line informula (xii') indicates the presence of a double bond in either the 4or 5 position of the dihydropyridine ring; the dotted line in formula(xiii') indicates the presence of a double bond in either the 2 or 3position of the dihydroquinoline ring;  is the skeleton of a sugarmolecule; n^(iv) is a positive integer equal to the total number of --OHfunctions in the sugar molecule from which said skeleton is derived;n^(v) is a positive integer one less than the total number of --OHfunctions in the sugar molecule from which said skeleton is derived;each A in each of structures (xii'), (xiii'), (xiv') and (xiv") canindependently be hydroxy or D', D' being the residue of a centrallyacting drug containing one reactive carboxyl functional group, saidresidue being characterized by the absence of a hydrogen atom from saidcarboxyl functional group in said drug; and ech R₄ in each of structures(x') and (xi') can independently be hydroxy, ##STR1634## wherein thedotted line is defined as with structures (xii') and (xiii'); D' isdefined as with structures (xii'), (xiii'), (xiv') and (xiv"); R₁ is C₁-C₇ alkyl, C₁ -C₇ haloalkyl or C₇ -C₁₀ aralkyl; and the depictedcarbonyl groupings can be attached at the 2, 3 or 4 position of thepyridinium or quinolinium ring or, except where otherwise specified, atthe 1, 3 or 4 position of the isoquinolinium ring; with the proviso thatat least one R₄ in each of structures (x') and (xi') is ##STR1635##wherein R₁, the dotted lines and the position of the carbonyl-containinggroupings are defined as above; and with the further proviso that whenmore than one of the R₄ radicals in a given compound are the aforesaidcarbonyl-containing groupings, then all such carbonyl-containinggroupings in said compound are identical.

(4') For Group (3) above: ##STR1636## wherein R is hydrogen, C₁ -C₇alkyl, C₃ -C₈ cycloalkyl, C₁ -C₇ haloalkyl, furyl, phenyl, or phenylsubstituted by one or more halo, lower alkyl, lower alkoxy, carbamoyl,lower alkoxycarbonyl, lower alkanoyloxy, lower haloalkyl, mono(loweralkyl)carbamoyl, di(lower alkyl)carbamoyl, lower alkylthio, loweralkylsulfinyl or lower alkylsulfonyl; the dotted line in formulas (k'),(l') and (m') indicates the presence of a double bond in either the 4 or5 position of the dihydropyridine ring; the dotted line in formulas(n'), (o') and (p') indicates the presence of a double bond in eitherthe 2 or 3 position of the dihydroquinoline ring; R₁ is C₁ -C₇ alkyl, C₁-C₇ haloalkyl or C₇ -CH₁₀ aralkyl; R₃ is C₁ to C₃ alkylene; X is--CONR'R", wherein R' and R", which can be the same or different, areeach H or C₁ -C₇ alkyl, or X is --CH═NOR" ' wherein R"' is H or C₁ -C₇alkyl; the carbonyl-containing groupings in formulas (k') and (m') andthe X substituent in formula (l') can each be attached at the 2, 3 or 4position of the dihydropyridine ring; the carbonyl-containing groupingsin formulas (n') and (p') and the X substituent in formula (o') can eachbe attached at the 2, 3 or 4 position of the dihydroquinoline ring; andthe carbonyl-containing groupings in formulas (q') and (s') and the Xsubstituent in formula (r') can each be attached at the 1, 3 or 4position of the dihydroisoquinoline ring.

The presently preferred dihydropyridine⃡pyridinium salt redox carriermoieties of this invention are those wherein R₁, when present, is C₃ ;R₃, when present, is --CH₂ CH₂ --; X, when present, is --CONH₂ ; thedepicted carbonyl-containing groupings in formulas (a) and (c) and the Xsubstituent in formula (b) are attached at the 3-position; the depictedcarbonyl-containing groupings in formulas (d) and (f) and the Xsubstituent in formula (e) are attached at the 3-position; the depictedcarbonyl-containing groupings in formulas (g) and (j) and the Xsubstituent in formula (h) are attached at the 4-position; Z', whenpresent, is C₂ or C₃ straight or branched alkylene; Q, when present, is--NH--; the X substituent in formulas (ii) and (v) and the depictedcarbonyl-containing groupings in formulas (i), (iii), (iv) and (vi) areattached at the 3-position; the X substituent in formula (viii) and thedepicted carbonyl-containing groupings encompassed by formulas (x),(xi), (xii), (xiii) and (xiv) are in the 3-position of the pyridinium orquinolinium ring and in the 4-position of the isoquinolinium ring; allR'₄ 's in structures (x) and (xi) are --OH except for the one R₄ in eachstructure which must be the carrier moiety; all A's in structures (xii),(xiii) and (xiv) are --OH;  is the skeleton of a glucose molecule; R informulas (k), (l) and (m) is hydrogen, methyl or CCl₃ ; and the depictedcarbonyl-containing groupings in formulas (k) through (s) are in the3-position of the pyridinium or quinolinium ring and in the 4-positionof the isoquinolinium ring; and the corresponding dihydro moieties.

Especially preferred dihydropyridine⃡pyridinium salt redox carriermoieties are the quaternaries of Group (1), structures (a), (b), (d),(e), (g) and (h); those of Group (2), structures (i), (ii), (iv), (v),(vii) (viii), (x) and (xii); and those of Group 3, structures (k), (l),(n), (o), (q) and (r); and the corresponding dihydro forms, mostespecially when they contain the preferred structural variablesidentified in the preceding paragraph.

From the foregoing, it is apparent that the present invention providestwo major classes of novel chemical compounds, i.e. the compounds ofgeneral formula (I) above, including their salts, and the compounds ofgeneral formula (II) above. Preferably, these two major clases consistof:

Compounds of the formula

    D--DHC].sub.n                                              (Ia)

and the nontoxic pharmaceutically acceptable salts thereof, wherein D isthe residue of a centrally acting drug containing at least one reactivefunctional group consisting of amino, hydroxyl, mercapto, carboxyl,amide and imide, said residue being characterized by the absence of ahydrogen atom from at least one of said reactive functional groups insaid drug; n is a positive integer equal to the number of saidfunctional groups from which a hydrogen atom is absent; and [DHC] is thereduced, biooxidizable, blood-brain barrier penetrating lipoidal form ofa dihydropyridine⃡pyridinium salt redox carrier;

with the proviso that when the compound is other than a salt of acompound of formula (Ia), when n is 1, when [DHC] is ##STR1637## whereinR₁ is C₁ -C₇ alkyl or C₇ -C₁₀ aralkyl, and when the centrally actingdrug of which D is the residue contains only one primary or secondary--OH functional group, no other --OH functional groups and no --NH₂,--NH--, --SH or --COOH functional groups, then D must be the residue ofa centrally acting drug other than a steroid sex hormone or long chainalkanol;

and with the further proviso that when the compound is other than a saltof a compound of formula (Ia), when n is 1, when [DHC] is ##STR1638##wherein R₁ is C₁ -C₇ alkyl or C₇ -C₁₀ aralkyl, and when the centrallyacting drug of which D is the residue contains only one --NH₂ functionalgroup and no other functional groups, then D must be the residue of acentrally acting drug other than a sympathetic stimulant; and

Quaternary salts of the formula

    D--QC.sup.+ ].sub.n qX.sup.-t                              (IIa)

wherein D and n are as defined with formula (Ia); [QC⁺ ] is thehydrophilic, ionic pyridinium salt form of a dihydropyridine⃡pyridiniumsalt redox carrier; X⁻ is the anion of a pharmaceutically acceptableorganic or inorganic acid; t is the valence of the acid anion; and q isthe number which when multiplied by t is equal to n;

with the proviso that when n is 1, when [QC⁺ ] is ##STR1639## wherein R₁is C₁ -C₇ alkyl or C₇ -C₁₀ aralkyl, and when the centrally acting drugof which D is the residue contains only one primary or secondary --OHfunctional group, no other --OH functional groups and no --NH₂, --NH--,--SH or --COOH functional groups, then D must be the residue of acentrally acting drug other than a steroid sex hormone or long chainalkanol;

and with the further proviso that when n is 1, when [QC⁺ ] is##STR1640## wherein R₁ is C₁ -C₇ alkyl or C₇ -C₁₀ aralkyl, and when thecentrally acting drug of which D is a residue contains only one --NH₂functional group and no other functional groups, then D must be theresidue of a centrally acting drug other than a sympathetic stimulant.

Within each of the classes (Ia) and (IIa), the following subclasses areparticularly noteworthy:

(A) Compounds of formulas (Ia) and (IIa) wherein the D portion of thecompound of formula (Ia) or (IIa) is identical to the correspondingportion of the centrally acting drug from which D can be considered tobe derived, and the carrier is attached through an amino functionalgroup in the drug. Preferred groups of compounds in this subclassinclude the following:

(1) Cerebral stimulants, including sympathomimetic amine-type cerebralstimulants, such as amphetamine, dextroamphetamine, levamphetamine,aletamine, cypenamine, tyramine, phentermine, methamphetamine,fencamfamin, zylofuramine, phenethylamine, etryptamine andtranylcypromine; tricyclic antidepressant-type cerebral stimulants,especially dibenzazepines and their analogues, e.g. desipramine,nortriptyline, protriptyline, maprotiline, octriptyline, and many othercerebral stimulants, alerting agents and antidepressants of varioustypes, as exemplified by amiphenazole, amedalin, cartazolate, daledalin,fluoxetine, nisoxetine, bupropion, difluamine and methylphenidate.

(2) Neurotransmitters, such as dopamine, histamine, tryptamine andserotonin.

(3) Narcotic analgesics, such as anileridine, noracymethadol andpiminodine.

(4) Hypotensives, such as clonidine, hydralazine, bethanidine,guanethidine, debrisoquin, propanolol and prizidilol.

(5) Sympathomimetic amines, such as ephedrine, oxymetazoline andpseudoephedrine.

(6) Anticancer and antitumor agents, such as doxorubicin and daunomycin.

(7) Antiviral agents, such as amantadine,2-guanidino-4,5-di-n-propyloxazole, 2-guanidino-4,5-diphenyloxazole,glucosamine and 6-amino-6-deoxy-D-glucose.

(8) Antibiotic and antibacterial agents, such as phenazopyridine,bacampicillin and pivampicillin.

(9) Sedatives, muscle relaxants, anticonvulsants, tranquilizers(including benzodiazepine tranquilizers) e.g. benzoctamine, tracazolate,chlordiazepoxide, tiletamine and aminoglutethimide.

(10) Diagnostics, including radiolabeled diagnostics, e.g.,iodometaraminol.

(B) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains an amino function through whichthe carrier is attached and also contains at least one --OH functionalgroup, and D in formula (Ia) or (IIa) contains, in place of the hydrogenatom of at least one of the --OH groups in the drug, at least onehydrolytically or metabolically cleavable hydroxyl protective group.Within subclass (B), preferred compounds are those in which D is aprotected residue of a neurotransmitter, such as dopamine or serotonin;a cerebral stimulant, such as tyramine; a sympathomimetic amine, such asephedrine, phenylephrine or pseudoephedrine; an adrenergic agent, suchas norepinephrine or epinephrine; an anticancer or antitumor agent, suchas pentostatin; an antiviral, such as glucosamine or6-amino-6-deoxy-D-glucose; or a hypotensive, such as atenolol ormetoprolol.

(C) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains an amino function through whichthe carrier is attached and also contains at least one --COOH functionalgroup, and D in formula (Ia) or (IIa) contains, in place of the hydrogenatom of at least one of the --COOH groups, at least one hydrolyticallyor metabolically cleavable carboxyl protective group. Preferredcompounds within this subclass are those in which D is a protectedresidue of anticancer and antitumor agents, e.g. melphalan, DON,L-alanosine and acivicin; antibiotics, especially penicillins such asamoxacillin and ampicillin and cephalosporins such as cephalexin,cefroxadine and ceforanide; hypotensives such as methyldopa andfurosemide; dopaminergic agents such as L-DOPA; and amino acids andsmall peptides containing 2-20 amino acid units, e.g. GABA, tyrosine andother natural amino acids, met⁵ -enkephalin, leu⁵ -enkephalin and thelike.

(D) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains an amino function through whichthe carrier is attached and also contains at least one --OH functionalgroup and at least one --COOH functional group, and D in formula (Ia) or(IIa) contains, in place of the hydrogen atom of at least one of the--OH functional groups and at least one of the --COOH functional groupsin said drug, respectively, at least one hydrolytically or metabolicallycleavable hydroxyl protective group and at least one hydrolytically ormetabolically cleavable carboxyl protective group. Of particularinterest are the compounds in which D is a protected residue of ahypotensive, e.g. methyldopa; or a sympathetic stimulant/dopaminergicagent, e.g. levodopa.

(E) Compounds of formulas (Ia) and (IIa) wherein the D portion of thecompound of formula (Ia) or (IIa) is identical to the correspondingportion of the drug from which D can be considered to be derived and thecarrier is attached through a hydroxyl or mercapto functional group inthe drug. Preferred groups of compounds in this subclass include thefollowing:

(1) Tranquilizers, including benzodiazepines, such as oxazepam,temazepam and lorazepam; phenothiazines, such as carphenazine,fluphenazine, acetophenazine and the like; and other tranquilizers suchas haloperidol, clopenthixol and hydroxyzine.

(2) Steroids, including androgens, e.g. testosterone; progestins, e.g.norgestrel and norethynodrel; estrogens, e.g. natural estrogens such asestradiol and semisynthetic estrogens such as mestranol; andantiinflammatory steroids such as cortisone, hydrocortisone,triamcinolone and the like.

(3) Narcotic analgesics, such as codeine, pentazocine and morphine.

(4) Narcotic antagonists and mixed agonists/antagonists, e.g.nalorphine, naloxone, buprenorphine, nalbuphine and butorphanol.

(5) Cerebral stimulants, including tricyclic antidepressants such asopipramol and centrally active hydroxylated metabolites of tricyclicantidepressants, e.g. 2-hydroxyimipramine.

(6) Anticancer and antitumor agents, e.g. mitoxantrone, etoposide,hydroxyurea and Ara-AC.

(7) Antivirals, e.g. ribavarin, acyclovir and trifluridine.

(8) Non-steroidal antiinflammatory agents, clonixeril and naproxol.

(9) Hypotensives, e.g. prizidilol and nadolol.

(10) Diagnostics, e.g. iopydol.

(F) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains a hydroxyl or mercapto functionthrough which the carrier is attached and also contains at least oneamino functional group, and D in the formula (Ia) or (IIa) contains, inplace of a hydrogen atom of at least one of the amino groups in thedrug, at least one amino protective group. Of particular interest arederivatives of neurotransmitters, stimulants, sympathetic amines,anticancer or antitumor agents, adrenergic agents and antiviral agents.The stimulants include centrally active metabolites of tricyclicantidepressants (e.g. 2-hydroxydesipramine).

(G) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains a hydroxyl or mercapto functionthrough which the carrier is attached and also contains at least onecarboxyl group, and D in formula (Ia) or (IIa) contains, in place of thehydrogen atom of at least one of the carboxyl groups in the drug, atleast one hydrolytically or metabolically cleavable carboxyl protectivegroup. Of particular interest here are the derivatives of valproic acidmetabolite anticonvulsants and CNS prostaglandins.

(H) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains an amide or imide or low pKaprimary or secondary amine function through which the carrier isattached and the D portion of the compound of formula (Ia) or (IIa) isidentical to the corresponding portion of the drug from which D can beconsidered to be derived. Especially significant members of this groupare the hydantoin anticonvulsants, e.g. phenytoin, ethotoin andmephenytoin, as well as other anti-convulsants, e.g. phenobarbital,aminoglutethimide, progabide and valpromide; tranquilizers, e.g.benzodiazepine-type tranquilizers such as bromazepam and oxazepam, andcentrally active N-desmethyl metabolites of N-methylated benzodiazepinetranquilizers; hypnotics; nonsteroidal antiinflammatory agents;anticancer agents such as cyclophosphamide; anti-depressants, such assulpiride; antibiotics, especially tetracyclines; and antivirals, suchas trifluridine.

(I) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains an amide or imide or low pKaprimary or secondary amine function through which the carrier isattached and the drug also contains at least one hydroxyl group, D informula (Ia) or (IIa) containing, in place of the hydrogen atom of atleast one hydroxyl group in the drug, at least one hydrolytically ormetabolically cleavable hydroxyl protective group. Significant membersof this group include antivirals such as trifluridine and benzodiazepinetranquilizers such as oxazepam.

(J) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains an amide or imide or low pKaprimary or secondary amine function through which the carrier isattached and the drug also contains at least one carboxyl functionalgroup, D in formula (Ia) or (IIa) containing, in place of the hydrogenatom of at least one --COOH in the drug, at least one hydrolytically ormetabolically cleavable carboxyl protective group. Especiallysignificant members of this group include anticancer and antitumoragents, antibiotics (particularly penicillins and cephalosporins) andCNS anticholinergics.

(K) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains a --COOH function through whichthe carrier is attached, and the D portion of the compound of formula(Ia) or (IIa) is identical to the corresponding portion of the drug fromwhich D can be considered to be derived. Especially significant membersof this group include nonsteroidal antiinflammatory agents such asnaproxen, ibuprofen and the like; diagnostics, including radiolabeledones such as o-iodohippuric acid and iothalamic acid, as well as thecorresponding "cold" compounds; CNS prostaglandins, such as PGD₂ ;antibiotics, especially cephalosporins and pencillins; anticonvulsants,e.g., valproic acid and SL 75102; anticancer and antitumor agents, e.g.chlorambucil, DACH and methotrexate.

(L) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains a --COOH function through whichthe carrier is attached and the drug also contains at least one hydroxylfunction, D in formula (Ia) or (IIa) containing, in place of thehydrogen atom of at least one --OH in the drug, at least onehydrolytically or metabolically cleavable hydroxyl protective group.Within this class, derivatives of valproic acid metabolite-typeanticonvulsants and NSAID's are especially noteworthy.

(M) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains a --COOH function which thecarrier is attached and the drug also contains at least one aminofunction, D in formula (Ia) or (IIa) containing, in place of a hydrogenatom of at least one of the amino functions in the drug, at least oneamino protective group. Significant members of this group includepenicillin antibiotics, cephalosporin antibiotics, anticancer andantitumor agents, amino acids and small peptides.

(N) Compounds of formulas (Ia) and (IIa) wherein the drug from which Dcan be considered to be derived contains a --COOH function through whichthe carrier is attached and the drug also contains at least one aminofunction and at least one hydroxyl function, D in formula (Ia) or (IIa)containing, in place of a hydrogen atom of at least one amino functionand in place of the hydrogen atom of at least one hydroxyl function,respectively, at least one amino protective group and at least onehydrolytically or metabolically cleavable hydroxyl protective group.Particularly significant members of this class include dopaminergicagents, hypotensive agents, antibiotics, hydroxyl-containing amino acids(e.g. tyrosine) and small peptides containing same.

It is apparent from the foregoing that the present invention provides awide variety of carrier moieties and compounds containing those carrierswhich are adapted for the site-specific and sustained delivery ofcentrally acting drugs to the brain. Many of the dihydro moieties whichare depicted as structures (a') through (j"), (k') through (s"), (i')through (ix") and (x') through (xiv') hereinabove, and the correspondingquaternary forms, as well as compounds containing those carriers, arespecifically contemplated by applicant's earlier copending applications,e.g. by Ser. No. 516,382. Moreover, applicant's earlier applications,and particularly Ser. No. 516,382, specifically contemplate someadditional carrier moieties and derivatives containing same, and thoseadditional carriers and derivatives are likewise within the ambit ofthis application. Among the classes of compounds specifically providedby both Ser. No. 516,382 and the present application, the following areparticularly noteworthy:

(A*) Compounds adapted for the side-specific/sustained delivery of acentrally acting drug species to the brain, said compounds being:

(i) compounds of the formula

    D*(--Q*).sub.n*                                            (I')

wherein D* is the residue of a centrally acting drug containing at leastone --NH₂ or --NH-- functional group, said residue being formed byremoval of a hydrogen atom from at least one of the --NH₂ or --NH--functional groups in said drug; n* is a positive integer equal to thenumber of said --NH₂ or --NH-- functional groups from which a hydrogenatom has been removed; and --Q* is a radical of the formula ##STR1641##wherein the dotted line in formulas (a*), (b*), (c*), (d*) and (e*)indicates the presence of a double bond in either the 4 or 5 position ofthe dihydropyridine ring; the dotted line in formulas (g*), (i*), (k*),(l*) and (n*) indicates the presence of a double bond in either the 2 or3 position of the dihydroquinoline ring; R₁ is C₁ -C₇ alkyl or C₇ -C₁₀aralkyl; R₃ is C₁ to C₃ alkylene; X is --CONR'R" wherein R' and R",which can be the same or different, are each H or C₁ -C₇ alkyl, or X is--CH═NOR"' wherein R"' is H or C₁ -C₇ alkyl; the ##STR1642## groupingsin formulas (a*), (b*), (c*) and (e*) and the X substituent in formula(d*) can each be attached at the 2, 3 or 4 position of thedihydropuyridine ring; the ##STR1643## groupings in formulas (g*), (i*),(k*) and (n*) and the X substituent in formula (l*) can each be attachedat the 2, 3 or 4 position of the dihydroquinoline ring; and the##STR1644## groupings in formulas (f*), (h*), (j*) and (o*) and the Xsubstituent in formula (m*) can each be attached at the 1, 3 or 4position of the dihydroisoquinoline ring; and

(ii) non-toxic pharmaceutically acceptable salts of compounds of formula(I');

with the proviso that when the compound is other than a salt as definedin (ii) above, when n* is 1, when --Q* is ##STR1645## wherein R₁ is C₁-C₇ alkyl or C₇ -C₂₀ aralkyl, and when the centrally acting drug fromwhich D* is derived contains only one --NH₂ functional group and noother functional groups, then D* must be the residue of a centrallyacting drug other than a sympathetic stimulant. The correspondingcompounds in which --Q* is (a*), (b*), (c*), (e*), (f*), (g*), (h*),(i*), (j*), (k*), (n*), (o*), (p*), (q*), (r*) or (t*) wherein R₁ is C₁-C₇ haloalkyl are also within the scope of class (A*) as defined herein.Within class (A*), preferred compounds are those wherein --Q* is aradical of the formula: ##STR1646## Also preferred are those compoundsof class (A*) wherein D* is the residue of hydralazine, bactobolin,clonidine, bethanidine, tranylcypromine, chlordiazepoxide,methamphetamine, phentermine, phenmetrazine, anileridine, protriptyline,daunamycin, dextroamphetamine, levamphetamine, amphetamine,phenylethylamine, doxorubicin, amantadine, mitoxantrone, tryptamine,desipramine or nortriptyline.

(B*) Compounds of Class (A*) as defined above, wherein the centrallyacting drug from which D* is derived also contains at least one --COOHfunctional group, and D* contains, in place of at least one of the--COOH functional groups in said drug, at least one --COOY' groupwherein Y' is a hydrolytically or metabolically cleavable carboxylprotective group. Within Class (B*), preferred compounds are those inwhich Y' is C₁ -C₇ alkyl and/or wherein D* is the residue of an aminoacid or of a peptide containing 2 to 20 amino acid segments (especiallyan enkephalin or an endorphin). Also preferred are the compounds ofClass (B*) wherein D* is the residue of tryptophan, ampicillin,cephalexin, melphalen, L-alanosine, DON, acivicin, GABA, γ-vinyl GABA,or γ-acetylenic GABA, met⁵ -enkephalin, leu⁵ -enkephalin, γ-endorphin,α-endorphin, β-endorphin, LH-RH, neurotensin, oxytocin M or vasopressin.

(C*) Compounds of Class (A*) as defined above, wherein the centrallyacting drug from which D* is derived also contains at least one --OHfunctional group, and D* contains, in place of at least one of the --OHfunctional groups in said drug, at least one --OY group wherein Y is ahydrolytically or metabolically cleavable hydroxyl protective group.Within Class (C*) preferred compounds are those wherein Y is an acylgroup or a carbonate group and/or wherein D* is the residue of aneurotransmitter, especially a catecholamine. At the present time,preferred compounds in this general class include those in which D* isthe residue of serotonin, norepinephrine, epinephrine, dopamine,tyramine or phenylephrine.

(D*) Compounds of Class (A*) as defined above, wherein the centrallyacting drug from which D* is derived also contains at least one --OHfunctional group and at least one --COOH functional group, and D*contains, in place of at least one of the --OH functional groups and atleast one of the --COOH functional groups in said drug, at least one--OY group and at least one --COOY' group, respectively, wherein Y is ahydrolytically or metabolically cleavable hydroxyl protective group andY' is a hydrolytically or metabolically cleavable carboxyl protectivegroup. Within Class (D*) preferred compounds are those wherein Y is anacyl group or a carbonate group and/or Y' is C₁ -C₇ alkyl. Of particularinterest are the compounds in which D* is the residue of methyldopa orlevodopa.

(E*) Compounds adapted for the site-specific/sustained delivery of acentrally acting drug species to the brain, said compounds being:

(i) compounds of the formula

    D"(--Q').sub.n'                                            (I")

wherein D" is the residue of a centrally acting drug containing at leastone --NH-- functional group which is part of an amide or imide structureor at least one low pKa primary or secondary amine functional group,said residue being formed by removal of a hydrogen atom from at leastone of said functional groups in said drug; n' is a positive integerequal to the number of said functional groups from which a hydrogen atomhas been removed; and --Q' is a radical of the formula ##STR1647##wherein the dotted lines indicate the presence of a double bond ineither the 4 or 5 position of the dihydropyridine ring and in either the2 or 3 position of the dihydroquinoline ring; R₁ is C₁ -C₇ alkyl or C₇-C₁₀ aralkyl; R is hydrogen, C₁ -C₇ alkyl, C₃ -C₈ cycloalkyl, C₁ -C₇alkyl substituted by one or more halogen atoms, pyridyl, furyl, phenyl,or phenyl substituted by one or more halo, lower alkyl, lower alkoxy,carbamoyl, lower alkoxycarbonyl, lower alkanoyloxy, lower haloalkyl,mono(lower alkyl)carbamoyl, di(lower alkyl)carbamoyl, lower alkylthiolower alkylsulfinyl or lower alkylsulfonyl; and the ##STR1648## groupingcan be in the 2, 3 or 4 position of the dihydropyridine ring, in the 2,3 or 4 position of the dihydroquinoline ring and in the 1, 3 or 4position of the dihydroisoquinoline ring; and

(ii) non-toxic pharmaceutically acceptable salts of compounds of formula(I"). Within Class (E*), preferred compounds are those wherein --Q is aradical of the formula ##STR1649## wherein R is as defined above,especially when R is hydrogen, methyl, phenyl or trichloromethyl, and/orwhen D" is the residue of a tetracycline antibiotic containing a --CONH₂function. Of particular interest in this general class are thosecompounds wherein D" is the residue of cyclophosphamide, ethotoin,phenobarbital, chlortetracycline, glutethimide, uracil mustard,bemegride, aminoglutethimide, phenytoin, butalbital, demeclocycline,minocycline, doxycycline, oxytetracycline, ethyl β-carboline3-carboxylate, nifedipine, methylphenidate, 3-deazaguanine, PCNU,spiromustine or L-ICRF.

(F*) Compounds adapted for the site-specific/sustained delivery of acentrally acting drug species to the brain, said compounds being:

(i) compounds of the formula

    (D"'(--Q").sub.n"                                          (I"')

wherein D"' is the residue of a centrally acting drug containing atleast one --OH-- or --SH functional group, said residue being formed byremoval of a hydrogen atom from at least one of the --OH or --SHfunctional groups in said drug; n" is a positive integer equal to thenumber of said --OH or --SH functional groups from which a hydrogen atomhas been removed; and --Q" is a radical of any one of formulas (a*)through (t*) inclusive as set forth in the definition of Class (A*)above, the structural variables in those formulas also being defined asin (A*) above; and

(ii) non-toxic pharmaceutically acceptable salts of compounds of formula(I"');

with the proviso that when the compound is other than a salt as definedin (ii) above, when n" is 1, when --Q" is ##STR1650## wherein R₁ is C₁-C₇ alkyl or C₇ -C₁₀ aralkyl, and when the centrally acting drug fromwhich D"' is derived contains only one primary or secondary --OHfunctional group, no other --OH functional groups and no --NH₂, --NH--,--SH or --COOH functional groups, then D"' must be the residue of acentrally acting drug other than a steriod sex hormone or long chainalkanol. The corresponding compounds in which --Q" is (a*), (b*), (c*),(e*), (f*), (g*), (h*), (i*), (j*), (k*), (n*), (o*), (p*), (q*), (r*)or (t*) wherein R₁ is C₁ -C₇ haloalkyl are also within the scope ofclass (F*) as defined herein. Within Class (F*), preferred compounds arethose in which --Q" is a radical of any one of formulas (a*') through(o*') set forth in connection with Class (A*) hereinabove. Alsopreferred are those compounds wherein D"' is a steroid sex hormone,i.e., an androgen, estrogen or progestin. When D"' is the residue of anandrogen, it is preferable the residue of testosterone or methyltestosterone or other known 17β-hydroxy-containing analogue oftestosterone. When D"' is the residue of an estrogen, it is preferablythe residue of a natural estrogen (estradiol, estrone or estriol) or ofa known semi-synthetic estrogen having a 17β-hydroxy substituent, suchas ethinyl estradiol, mestranol or quinestrol. When D"' is the residueof a progestin, it is preferably the residue of a known semi-syntheticprogestin having a 17β-hydroxy substituent, such as norethindrone,norgestrel, ethisterone, dimethisterone, allylestrenol, cingestol,ethynerone, lynestrenol, norgesterone, norvinisterone, ethynodiol,oxogestone, tigestol or norethynodrel. Within Class (F*), anotherpreferred group of compounds consists of the compounds in which D"' isthe residue of an anti-inflammatory steroid, especially a knownanti-inflammatory steroid having a 21-hydroxy substituent, such ascortisone, hydrocortisone, betamethasone, dexamethasone, flumethasone,fluprednisolone, methyl prednisolone, meprednisone, prednisolone,prednisone, cortodoxone, fludrocortisone, paramethasone ortriamcinolone. Yet another preferred group of Class (F*) compounds isthe group in which D"' is the residue of a narcotic analgesic, narcoticantagonist or narcotic agonist-antagonist, especially when it is theresidue of a known compound of this type bearing at least one hydroxysubstituent, such as codeine, pentazocine, naloxone, oxycodone,hydromorphone, oxymorphone, nalorphine, morphine, levorphanol,meptazinol, cyclazocine, phenazocine, profadol, metopon, drocode,myfadol, buprenorphine, nalbuphine, butorphanol, levallorphan,naltrexone, alazocine, oxilorphan or nalmexone. Still another preferredgroup of Class (F*) compounds consist of compounds in which D"' is theresidue of an anticancer or antitumor agent; preferably D"' is theresidue of a podophyllotoxin derivative (especially etoposide orteniposide) or of Ara-AC, pentostatin, thioguanine, hydroxyurea,dihydro-5-azacytidine, tiazofurin, sangivamycin, Ara-A, 6-MMPR,trimethyl TMM, SR-2555, bisbenzimidazole, SR-2508, aclacinomycin A,phyllanthoside, 6-mercaptopurine, desmethylisonidazole, menogarol,aphidicolin, 5-FUDR, trifluoroacetyl doxorubicin, cytosine arabinoside,5-azacytidine, Ara-C or streptozotocin. Yet another preferred group ofcompounds within this general class consists of compounds in which D"'is the residue of an antiviral agent such as ribavarin, acyclovir, synoranti-6-[[(hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1H-benzimidazol-2-amine,5,7-dimethyl-2-β-D-ribofuranosyl-s-triazole(1,5-a)pyrimidine,2-deoxy-D-glucose, 2-deoxy-2-fluoro-D-mannose,phenyl-6-chloro-6-deoxy-β-D-glucopyranoside,(S)-9-(2,3-dihydroxypropyl)adenine, idoxuridine,5,6-dichloro-1-β-D-ribofuranosylbenzimidazole orbisihydroxyvinyluridine. Another preferred group of compounds in Class(F*) consists of compounds in which D"' is the residue of abenzodiazepine or phenothiazine tranquilizer, especially those in whichD"' is the residue of a known benzodiazepine such oxazepam, lorazepam ortemazepam, or of a known phenothiazine such as acetophenazine,carphenazine, fluphenazine, perphenazine or piperacetazine. Other Class(F*) compounds of interest are those in which D"' is the residue ofthiopental, haloperidol, opipramol, clopenthixol, ethamivan,hydroxyzine, apomorphine, iopydol, clindamycin, lincomycin, benzestrol,diethylstilbestrol, pholcodeine or dipyridamole.

(G*) Compounds of Class (F*) as defined above, wherein the centrallyacting drug from which D"' is derived also contains at least one --COOHfunctional group, and D"' contains, in place of at least one of the--COOH functional groups in said drug, at least one --COOY' groupwherein Y' is a hydrolytically or metabolically cleavable carboxylprotective group. Within Class (G*), preferred compounds include thosein which D"' is the residue of a valproic acid metabolite (such as5-hydroxy-2-n-propylpentanoic acid, 4-hydroxy-2-n-propylpentanoic acidor 3-hydroxy-2-n-propylpentanoic acid), clorazepate or diflunisal.

(H*) Compounds of Class (F*) as defined above, wherein --Q" is a radicalof the formula ##STR1651## and D"' is the residue of a centrally actingdrug containing a hindered tertiary --OH functional group; especiallywhen D"' is the residue of biperiden, cycrimine, procyclidine ortrihexylphenidyl.

(I*) Compounds adapted for the site-specific/sustained delivery of acentrally acting drug species to the brain, said compounds being:

(i) compounds of the formula

    D.sup.iv (--Q"').sub.n"'                                   (I.sup.iv)

wherein D^(iv) is the residue of a centrally acting drug speciescontaining at least one --COOH functional group, said residue beingformed by removal of an --OH from at least one of the --COOH functionalgroups in said drug; n"' is a positive integer equal to the number ofsaid --COOH functional groups from which an --OH has been removed; and--Q"' is a radical of the formula ##STR1652## wherein Z' is C₁ -C₈straight or branched alkylene;

(ii) compounds of the formula ##STR1653## wherein D^(iv) is defined asabove and each R₄ * can independently be hydrogen, D^(iv) or a radicalof the formula ##STR1654## with the proviso that at least one R₄ * is aradical of the formula ##STR1655##

(iii) compounds of the formula ##STR1656## wherein D^(iv) is defined asabove, ○ is the skeleton of a sugar molecule, n^(iv) is a positiveinteger equal to the total number of --OH functions in the sugarmolecule from which said skeleton is derived, and R₄ * can independentlybe hydrogen, D^(iv) or a radical of the formula ##STR1657## with theproviso that at least one R₄ * is a radical of the formula and

(iv) non-toxic pharmaceutically acceptable salts of compounds of formula(I^(iv)), (I^(v)) and (I^(vi)). Within this class, preferred compoundsare those in which z' is ##STR1658## and/or in which ○ is the skeletonof a pentose or hexose, especially when ○ is ##STR1659## Also preferredClass (I*) compounds are those in which D^(iv) is the residue of anantibiotic, a radiodiagnostic, a non-steroidal anti-inflammatory agentor an anticancer or antitumor agent. At the present time, compounds ofparticular interest within this class are those in which D^(iv) is theresidue of cephalothin, valproic acid, cefoxitin, clorazepate,iodopyracet, iodouppurate, iodamide, iopanoic acid, nalidixic acid,amoxicillin, oxolinic acid, chlorambucil, glyoxylic acidsulfonylhydrazone, DACH, methotrexate, aminopterin,5-methyltetrahydrohomofolic acid, cefazolin, ibuprofen, naproxen,flurbiprofen, zomepirac, mefenamic acid, sulindac, diclofenac,indomethacin, benzylpenicillin, phenoxymethylpenicillin, methicillin,nafcillin, ticarcillin, furosemide, oxacillin, carbenicillin,dicloxacillin, fenbufen, fenoprofen, indoprofen, ketoprofen, fluprofen,bucloxic acid, tolmetin, alclofenac, fenclozic acid, ibufenac,meclofenamic acid, flufenamic acid or flufenisal.

(J*) Compounds adapted for the site-specific/sustained delivery of anbenzodiazepine tranquilizer to the brain, said compounds having theformula ##STR1660## and the nontoxic pharmaceutically acceptable saltsthereof, wherein --Q* is as defined in connection with Class (A*) aboveand X, Y and Z are identical to the corresponding groupings in a knownbenzodiazepine tranquilizer having the formula ##STR1661## especiallywhen --Q* is a radical of any one of formulas (a*') through (o*') setforth in connection with Class (A*) hereinabove. Presently preferredcompounds in this class are those having the formula ##STR1662##

(K*) Non-toxic pharmaceutically acceptable quaternary salts having theformula

    D*(--Q.sup.*⊕).sub.n* Y.sub.n*.sup.⊖           (II')

wherein D* and n* are as defined in connection with Class (A*), Y⊖ isthe anion of a non-toxic pharmaceutically acceptable acid and --Q^(*)⊕has the formula ##STR1663## wherein R₁ is C₁ -C₇ alkyl or C₇ -C₁₀aralkyl; R₃ is C₁ to C₃ alkylene; X is --CONR'R" wherein R' and R",which can be the same or different, are each H or C₁ -C₇ alkyl, or X is--CH═NOR"' wherein R"' is H or C₁ -C₇ alkyl; the ##STR1664## groupingsin formulas (aa*), (bb*), (cc*) and (ee*) and the X substituent informula (dd*) can each be attached at the 2, 3 or 4 position of thepyridinium ring; the ##STR1665## groupings in formulas (gg*), (ii*),(kk*) and (nn*) and the X substituent in formula (ll*) can each beattached at the 2, 3 or 4 position of the quinolinium ring; and the##STR1666## groupings in formulas (ff*) (hh*), (jj*) and (oo*) and the Xsubstituent in formula (mm*) can each be attached at the 1 3 or 4position of the isoquinolinium ring; with the proviso that when n* is 1,when --Q^(*)⊕ is ##STR1667## wherein R₁ is C₁ -C₇ alkyl or C₇ -C₁₀aralkyl, and when the centrally acting drug from which D* is derivedcontains only one --NH₂ functional group and no other functional groups,then D* must be the residue of a centrally acting drug other than asympathetic stimulant. The corresponding compounds in which --Q^(*)⊕ is(aa*), (bb*), (cc*), (ee*), (ff*), (gg*), (hh*), (ii*), (jj*), (kk*),(nn*), (oo*), (pp*), (qq*), (rr*) or (tt*) wherein R₁ is C₁ -C₇haloalkyl are also within the scope of class (K*) as defined herein.Within this class of compounds, preferred compounds are those wherein--Q^(*)⊕ has the formula: ##STR1668##

(L*) Non-toxic pharmaceutically acceptable quaternary salts having theformula

    D"(--Q'.sup.⊕).sub.n' Y.sub.n'.sup.⊖           (II")

wherein D" and n' are as defined in connection with Class (E*) above,Y.sup.⊖ is the anion of a non-toxic pharmaceutically acceptable acid and--Q'.sup.⊕ has the formula ##STR1669## wherein R₁ is C₁ -C₇ alkyl or C₇-C₁₀ aralkyl; R is hydrogen, C₁ -C₇ alkyl, C₃ -C₈ cycloalkyl, C₁ -C₇alkyl substituted by one or more halogen atoms, pyridyl, furyl, phenyl,or phenyl substituted by one or more halo, lower alkyl, lower alkoxy,carbamouyl, lower alkoxycarbonyl, lower alkanoyloxy, lower haloalkyl,mono (lower alkyl)carbamoyl, di(lower alkyl)carbamoyl, lower alkylthio,lower alkylsulfinyl and lower alkylsulfonyl; and the ##STR1670##grouping can be in the 2, 3 or 4 position of the pyridinium ring, in the2, 3 or 4 position of the quinolinium ring and in the 1, 3 or 4 positionof the isoquinolinium ring.

(M*) Non-toxic pharmaceutically acceptable quaternary salts having theformula

    D"'(--Q".sup.⊕).sub.n" Y.sub.n".sup.⊖          (II"')

wherein D"' and n" are as defined in connection with Class (F*) above,Y.sup.⊖ is the anion of a non-toxic pharmaceutically acceptable acid and--Q".sup.⊕ has any one of formulas (aa*) through (oo*) set forth inconnection with Class (K*) above, wherein the various substituents aredefined as in (K*) above; with the proviso that when n" is 1, when--Q".sup.⊕ is ##STR1671## where R₁ is C₁ -C₇ alkyl or C₇ -C₁₀ aralkyl,and when the centrally acting drug from which D"' is derived containsonly one primary or secondary --OH functional group, no other --OHfunctional groups and no --NH₂, --NH--, --SH or --COOH functionalgroups, then D"' must be the residue of a centrally acting drug otherthan a steroid sex hormone or long chain alkanol. The correspondingcompounds in which --Q".sup.⊕ is (aa*), (bb*), (cc*), (ee*), (ff*),(gg*), (hh*), (ii*), (jj*), (kk*), (nn*), (oo*) (pp*) (qq*) (rr*) or(tt*) wherein R₁ is C₁ -C₇ haloalkyl are also within the scope of class(M*) as defined herein. Within Class (M*), preferred compounds are thosein which --Q".sup.⊕ has any one of formulas (aa') through (oo') setforth in connection with Class (K*) above.

(N*) Non-toxic pharmaceutically acceptable quaternary salts having theformula:

    (i) D.sup.iv (--Q"'.sup.⊕).sub.n"' Y.sub.n"'.sup.⊖(II.sup.iv)

wherein D^(iv) an n"' are as defined in connection with Class (I*)above, Y.sup.⊖ is the anin of a non-toxic pharmaceutically acceptableacid and --Q"'.sup.⊕ has the formula ##STR1672## wherein Z' is C₁ -C₈straight or branched alkylene; ##STR1673## wherein D^(iv) is as definedin connection with Class (I*) above and each R₄ *' can independently behydrogen, D^(iv) or ##STR1674## wherein Y.sup.⊖ is defined as above,with the proviso that at least one R₄ *' is ##STR1675## wherein D^(iv)and ○ are as defined in connection with Class (I*) above, and each R₄ *'can independently be hydrogen, D^(iv) or ##STR1676## wherein Y.sup.⊖ isdefined as above, with the proviso that at least one R₄ *' is##STR1677##

Accordingly, provided hereby are not only a generic method and novelclass of pro-prodrugs for the specific and/or target enhanced deliveryto the brain of a wide variety of drug species via the bidirectionaltransport of the drug species into and out of the brain employingdihydropyridine ⃡pyridinium salt carrier redox systems, but also asystem providing insight into the basic transport processes (both activeand passive) of, and enzymatic activities in, the blood-brain barrier,as well as into the various processes specific to the function of thebrain. Again, another very significant aspect of the bioreversible redoxdelivery system according to this invention is the toxicity implication,for significantly reduced is systemic toxicity by accelerating theelimination of the drug/quaternary carrier system. And even centraltoxicity is reduced by providing for low level, sustained release of theactive drug species in the brain. Low toxicity is provided both asregards the quaternary carrier and in combination with the drug. Again,the present invention is not bases on a simple prodrug concept, as wasthe case with the earlier work done with 2-PAM In that case, ahydrophilic compound (2-PAM) was made lipoidal by making itsdihydropyridine form (Pro-2-PAM) to enable its peenetration throughlipoidal barriers. This allowed the compound to get into the brain aswell as other organs, but this prodrug manipulation did not and couldnot result in any brain specificity. And while the possibility ofcarrying drugs to the brain was also hypothesized earlier, all theexperimental evidence reported in the literature negates any possiblespecificity, for the only compound delivered to the brain (2-PAM viaPro-2-PAM) showed similar efflux properties from the brain as from theother organs. There is no suggestion in the art of the brain-specificdelivery which has now been achieved and which is a result of asurprisingly slow in vivo oxidation of the dihydro carrier systemcompared to the one reported in the earlier 2-PAM⃡Pro-2-PAM system.Indeed, a most surprising and unexpected feature of the present deliverysystem is that it will result in a build-up of the concentration of theintermediate charged species (quarternary form) in the brain even afterone single bolus injection of the starting lipophilic chemical deliverysystem (dihydro form). There is a first portion of the brain levelversus time curve which shows a significant increase in the brain (up todoubling or even more) from the starting overall concentration, and thisprocess takes place against the concentration gradient; see, for examle,FIG. 6 (dopamine) and FIG. 8 (testosterone). The blood levels dosimultaneously fall, and ater some time (for example, for 1 to 11/2hours) significantly higher concentrations of the precursor, now in itshydrophilic carrier (quaternary) form, will be found in the brain ascompared to the rest of the body. This is brain-specific delivery; it isnot simply delivery of something which otherwise cannot get to thebrain, but is delivery of a given agent in an inactive form specificallyto the brain, which then will subsequently lead to a sustainedbrain-specific delivery of the active specie itself. In the case oftestosterone and dopamine, for example, slow enzymatic cleavage of thequaternary form "locked in" the brain provides sustained release of thedrug itself.

While the invention has been described in terms of various preferredembodiments, the skilled artisan will appreciate that variousmodifications, substitutions,omissions, and changes may be made withoutdeparting from the spirit thereof. Accordingly, it is intended that thescope of the present invention be limited solely by the scope of thefollowing claims.

What is claimed is:
 1. A compound of the formula

    D--DHC].sub.n                                              (Ia)

or a non-toxic pharmaceutically acceptable salt thereof, wherein D isthe residue of a steroidal female sex hormone having one or two reactivehydroxyl functional groups, one such hydroxyl group being a 17β-hydroxysubstituent, said residue having a hydrogen atom absent from at leastone of said reactive hydroxyl functional groups in said drug, saidsteroidal female sex hormone being selected from the group consisting ofestradiol, ethisterone, ethinyl estradiol, mestranol, norgestrel,norethindrone, norethynodrel, norgensterone, norvinisterone andethynodiol; n is a positive integer equal to the number of saidfunctional groups from which a hydrogen atom is absent; and [DHC] is aradical of the formula ##STR1678## wherein the dotted line indicates thepresence of a double bond in either the 4 and 5 position of thedihydropyridine ring; R₁ is C₁ -C₇ alkyl, C₁ -C₇ haloalkyl or C₇ -C₁₀aralkyl; and the carbonyl grouping is attached at the 2, 3 or 4 positionof the dihydropyridine ring.
 2. A compound according to claim 1 wherein[DHC] is a radical of the formula ##STR1679##
 3. A compound according toclaim 1 wherein D is a residue of estradiol.
 4. A compound according toclaim 1 wherein D is the residue of ethisterone.
 5. A compound accordingto claim 1 wherein D is a residue of ethinyl estradiol.
 6. A compoundaccording to claim 1 wherein D is the residue of mestranol.
 7. Acompound according to claim 1 wherein D is the residue of methyltestosterone.
 8. A compound according to claim 1 wherein D is theresidue of norgestrel.
 9. A compound according to claim 1 wherein D isthe residue of norethindrone.
 10. A compound according to claim 1wherein D is the residue of norethynodrel.
 11. A compound according toclaim 1 wherein D is the residue of norgesterone.
 12. A compoundaccording to claim 1 wherein D is the residue of norvinisterone.
 13. Acompound according to claim 1 wherein D is a residue of ethynodiol. 14.A compound according to claim 1, having the structural formula##STR1680##
 15. A compound according to claim 1, having the structuralformula ##STR1681##
 16. A compound according to claim 1, having thestructural formula ##STR1682##
 17. A compound according to claim 1,having the structural formula ##STR1683##
 18. A compound according toclaim 1, having the structural formula ##STR1684##
 19. A compoundaccording to claim 1, having the structural formula ##STR1685##
 20. Acompound according to claim 1, having the structural formula ##STR1686##21. A compound according to claim 1, having the structural formula##STR1687##
 22. A compound according to claim 1, having the structuralformula ##STR1688##
 23. A compound according to claim 1, having thestructural formula ##STR1689##
 24. A compound according to claim 1,having the structural formula ##STR1690##
 25. A compound according toclaim 1, having the structural formula ##STR1691##
 26. A compoundaccording to claim 1, having the structural formula ##STR1692##
 27. Aquaternary salt of the formula

    D--OC.sup.+ ].sub.n qX.sup.-t                              (IIa)

wherein D is the residue of a steroidal female sex hormone having one ortwo reactive hydroxyl functional groups, one such hydroxyl group being a17β-hydroxy substituent, said residue having a hydrogen atom absent fromat least one of said reactive hydroxyl functional groups in said drug,said steroidal female sex hormone being selected from the groupconsisting of estradiol, ethisterone, ethinyl estradiol, mestranol,norgestrel, norethindrone, norethynodrel, norgesterone, norvinisteroneand ethynodiol; n is a positive integer equal to the number of saidfunctional groups from which a hydrogen atom is absent; X⁻ is the anionof a pharmaceutically acceptable organic or inorganic acid; t is thevalence of the acid anion; q is the number which when multiplied by t isequal to n; and [QC⁺ ] is a radical of the formula ##STR1693## whereinR₁ is C₁ -C₇ alkyl, C₁ -C₇ haloalkyl or C₇ -C₁₀ aralkyl; and thecarbonyl grouping is attached at the 2, 3 or 4 position of thepyridinium ring.
 28. A quaternary salt according to claim 27 wherein[QC⁺ ] is a radical of the formula ##STR1694##
 29. A quaternary saltaccording to claim 27 wherein D is a residue of estradiol.
 30. Aquaternary salt according to claim 27 wherein D is the residue ofethisterone.
 31. A quaternary salt according to claim 27 wherein D is aresidue of ethinyl estradiol.
 32. A quaternary salt according to claim27 wherein D is the residue of mestranol.
 33. A quaternary saltaccording to claim 27 wherein D is the residue of methyl testosterone.34. A quaternary salt according to claim 27 wherein D is the residue ofnorgestrel.
 35. A quaternary salt according to claim 27 wherein D is theresidue of norethindrone.
 36. A quaternary salt according to claim 27wherein D is the residue of norethynodrel.
 37. A quaternary saltaccording to claim 27 wherein D is the residue of norgesterone.
 38. Aquaternary salt according to claim 27 wherein D is the residue ofnorvinisterone.
 39. A quaternary salt according to claim 27 wherein D isa residue of ethynodiol.
 40. A quaternary salt according to claim 27having the structural formula ##STR1695##
 41. A quaternary saltaccording to claim 27, having the structural formula ##STR1696##